Investments in and Advances to Unconsolidated Affiliates - Unconsolidated Affiliates - Schedule of Condensed Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Combined and Condensed Balance Sheets
Real estate under development	$ 189,387	$ 173,702
Other assets	209,875	214,959
Total assets	3,918,716	3,960,247	$ 4,092,957
Total liabilities and equity	3,918,716	3,960,247
Company's share of distributions in excess of income from and investments in unconsolidated affiliates	15,596	15,292
Investments in and advances to unconsolidated affiliates	301,717	302,070
Unconsolidated Affiliates
Combined and Condensed Balance Sheets
Rental property, net	526,857	518,900
Real estate under development		26,681
Investment in unconsolidated affiliates	6,853	6,853
Other assets	90,143	100,901
Total assets	623,853	653,335
Mortgage notes payable	406,117	405,652
Other liabilities	56,060	61,932
Partners’ equity	161,676	185,751
Total liabilities and equity	623,853	653,335
Company's share of accumulated equity	179,029	185,533
Basis differential	104,810	95,358
Deferred fees, net of portion related to the Company's interest	2,169	3,472
Amounts receivable by the Company	113	2,415
Investments in and advances to unconsolidated affiliates, net of Company's share of distributions in excess of income from and investments in unconsolidated affiliates	286,121	286,778
Company's share of distributions in excess of income from and investments in unconsolidated affiliates	15,596	15,292
Investments in and advances to unconsolidated affiliates	$ 301,717	$ 302,070