| Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax | en-US | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax, Total | en-US | http://www.xbrl.org/2003/role/totalLabel | http://www.xbrl.org/2003/role/link |
| Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. | en-US | http://www.xbrl.org/2003/role/documentation | http://www.xbrl.org/2003/role/link |