Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Assets
Rental properties, net of accumulated depreciation of $583,848 and $534,303 at June 30, 2016 and December 31, 2015, respectively	$ 3,331,781	$ 3,025,199
Land held for development	22,530	23,610
Property under development	301,605	378,920
Mortgage notes and related accrued interest receivable	424,875	423,780
Investment in a direct financing lease, net	188,386	190,880
Investment in joint ventures	5,955	6,168
Cash and cash equivalents	8,462	4,283
Restricted cash	16,614	10,578
Accounts receivable, net	62,061	59,101
Other assets	97,955	94,751
Total assets	4,460,224	4,217,270
Liabilities:
Accounts payable and accrued liabilities	91,130	92,178
Common dividends payable	20,360	18,401
Preferred dividends payable	5,952	5,951
Unearned rents and interest	49,798	44,952
Debt	2,098,265	1,981,920
Total liabilities	2,265,505	2,143,402
Equity:
Common Shares, $.01 par value; 100,000,000 shares authorized; and 66,154,679 and 63,195,182 shares issued at June 30, 2016 and December 31, 2015, respectively	662	632
Preferred shares, $.01 par value; 25,000,000 shares authorized:
Additional paid-in-capital	2,665,663	2,508,445
Treasury shares at cost: 2,529,510 and 2,371,198 common shares at June 30, 2016 and December 31, 2015, respectively	(107,133)	(97,328)
Accumulated other comprehensive income	3,485	5,622
Distributions in excess of net income	(368,097)	(343,642)
Total equity	2,194,719	2,073,868
Total liabilities and equity	4,460,224	4,217,270
Series C Preferred Shares [Member]
Preferred shares, $.01 par value; 25,000,000 shares authorized:
Preferred shares	54	54
Series E Preferred Shares [Member]
Preferred shares, $.01 par value; 25,000,000 shares authorized:
Preferred shares	35	35
Series F Preferred Stock [Member]
Preferred shares, $.01 par value; 25,000,000 shares authorized:
Preferred shares	$ 50	$ 50