SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION - Summary (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Carrying cost
Balance at beginning of period	$ 949,838	$ 937,617	$ 900,095
Acquisitions	206,340	11,650	19,040
Improvements	33,463	48,102	30,597
Conversion of mortgage loans into owned properties	10,600
Capitalized interest	827	1,506	932
Other non-cash items (See Note 4)	2,882	304	479
Conveyed land (See Note 4)	(670)
Cost of real estate sold	(2,344)	(49,341)	(13,526)
Impairment on real estate for sale	(2,250)
Ending balance	1,198,686	949,838	937,617
Accumulated depreciation
Balance at beginning of period	223,315	218,700	198,548
Depreciation expense	29,329	25,424	24,568
Cost of real estate sold	(1,379)	(20,809)	(4,416)
Ending balance	$ 251,265	$ 223,315	$ 218,700