 | us-gaap:InvestmentIncomeAmortizationOfDiscount | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:InvestmentIncomeAmortizationOfPremium | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:InvestmentIncomeNetAmortizationOfDiscountAndPremium | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternative |
 | us-gaap:InvestmentIncomeAmortizationOfDiscount | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:InvestmentIncomeAmortizationOfPremium | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:InvestmentIncomeNetAmortizationOfDiscountAndPremium | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeAlternativeStatementTable |
 | us-gaap:InvestmentIncomeAmortizationOfDiscount | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateExcludingREITs |
 | us-gaap:InvestmentIncomeAmortizationOfPremium | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateExcludingREITs |
 | us-gaap:InvestmentIncomeNetAmortizationOfDiscountAndPremium | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateExcludingREITs |
 | us-gaap:InvestmentIncomeAmortizationOfDiscount | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateExcludingREITsStatementTable |
 | us-gaap:InvestmentIncomeAmortizationOfPremium | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateExcludingREITsStatementTable |
 | us-gaap:InvestmentIncomeNetAmortizationOfDiscountAndPremium | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateExcludingREITsStatementTable |
 | us-gaap:InvestmentIncomeAmortizationOfDiscount | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateInvestmentTrusts |
 | us-gaap:InvestmentIncomeAmortizationOfPremium | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateInvestmentTrusts |
 | us-gaap:InvestmentIncomeNetAmortizationOfDiscountAndPremium | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateInvestmentTrusts |
 | us-gaap:InvestmentIncomeAmortizationOfDiscount | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateInvestmentTrustsStatementTable |
 | us-gaap:InvestmentIncomeAmortizationOfPremium | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateInvestmentTrustsStatementTable |
 | us-gaap:InvestmentIncomeNetAmortizationOfDiscountAndPremium | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeRealEstateInvestmentTrustsStatementTable |
 | us-gaap:InvestmentIncomeAmortizationOfDiscount | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:InvestmentIncomeAmortizationOfPremium | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:InvestmentIncomeNetAmortizationOfDiscountAndPremium | parent-child | http://fasb.org/us-gaap/role/statement/StatementOfIncome |
 | us-gaap:InvestmentIncomeAmortizationOfDiscount | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:InvestmentIncomeAmortizationOfPremium | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:InvestmentIncomeNetAmortizationOfDiscountAndPremium | domain-member | http://fasb.org/us-gaap/role/statement/StatementOfIncomeStatementTable |
 | us-gaap:InvestmentIncomeAmortizationOfDiscount | parent-child | http://fasb.org/us-gaap/role/disclosure/InvestmentsDebtAndEquitySecurities |
 | us-gaap:InvestmentIncomeAmortizationOfPremium | parent-child | http://fasb.org/us-gaap/role/disclosure/InvestmentsDebtAndEquitySecurities |
 | us-gaap:InvestmentIncomeNetAmortizationOfDiscountAndPremium | parent-child | http://fasb.org/us-gaap/role/disclosure/InvestmentsDebtAndEquitySecurities |
 | us-gaap:InvestmentIncomeAmortizationOfDiscount | domain-member | http://fasb.org/us-gaap/role/disclosure/InvestmentsDebtAndEquitySecuritiesScheduleOfInvestmentIncomeReportedAmountsByCategoryTable |
 | us-gaap:InvestmentIncomeAmortizationOfPremium | domain-member | http://fasb.org/us-gaap/role/disclosure/InvestmentsDebtAndEquitySecuritiesScheduleOfInvestmentIncomeReportedAmountsByCategoryTable |
 | us-gaap:InvestmentIncomeNetAmortizationOfDiscountAndPremium | domain-member | http://fasb.org/us-gaap/role/disclosure/InvestmentsDebtAndEquitySecuritiesScheduleOfInvestmentIncomeReportedAmountsByCategoryTable |