| 開発事業営業利益又は開発事業営業損失(△) | ja | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| 開発事業営業利益又は開発事業営業損失(△)、鉄道事業 | ja | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| 開発事業営業損失(△) | ja | http://www.xbrl.org/2003/role/negativeLabel | http://www.xbrl.org/2003/role/link |
| 開発事業営業利益 | ja | http://www.xbrl.org/2003/role/positiveLabel | http://www.xbrl.org/2003/role/link |
| Operating profit (loss) - development | en | http://www.xbrl.org/2003/role/label | http://www.xbrl.org/2003/role/link |
| Operating profit (loss) - development - RWY | en | http://www.xbrl.org/2003/role/verboseLabel | http://www.xbrl.org/2003/role/link |
| Operating loss - development | en | http://www.xbrl.org/2003/role/negativeLabel | http://www.xbrl.org/2003/role/link |
| Operating profit - development | en | http://www.xbrl.org/2003/role/positiveLabel | http://www.xbrl.org/2003/role/link |