Schedule III - Real Estate and Accumulated Depreciation - Real Estate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Real Estate
Balance at the beginning of the period	$ 944,346	$ 917,835	$ 819,591
Reclassification of intangibles to accumulated amortization		1,316
Improvements and additions	270,551	75,345	232,582
Acquisitions through foreclosures			6,706
Dispositions	(21,793)	(50,150)	(141,044)
Balance at the end of the period	1,193,104	944,346	917,835
Commercial Real Estate
Reconciliation of Real Estate
Balance at the beginning of the period	901,797	842,140	697,965
Reclassification of intangibles to accumulated amortization		1,316
Improvements and additions	233,561	72,963	230,915
Acquisitions through foreclosures			6,706
Dispositions	0	(14,622)	(93,446)
Balance at the end of the period	1,135,358	901,797	842,140
Residential Real Estate
Reconciliation of Real Estate
Balance at the beginning of the period	42,549	75,695	121,626
Reclassification of intangibles to accumulated amortization		0
Improvements and additions	36,990	2,382	1,667
Acquisitions through foreclosures			0
Dispositions	(21,793)	(35,528)	(47,598)
Balance at the end of the period	$ 57,746	$ 42,549	$ 75,695