Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Assets
Rental properties, net of accumulated depreciation of $562,195 and $534,303 at March 31, 2016 and December 31, 2015, respectively	$ 3,214,347	$ 3,025,199
Land held for development	22,530	23,610
Property under development	266,574	378,920
Mortgage notes and related accrued interest receivable	457,429	423,780
Investment in a direct financing lease, net	191,720	190,880
Investment in joint ventures	5,869	6,168
Cash and cash equivalents	10,980	4,283
Restricted cash	23,428	10,578
Accounts receivable, net	62,403	59,101
Other assets	88,260	94,751
Total assets	4,343,540	4,217,270
Liabilities:
Accounts payable and accrued liabilities	77,523	92,178
Common dividends payable	20,269	18,401
Preferred dividends payable	5,952	5,951
Unearned rents and interest	56,627	44,952
Debt	1,996,131	1,981,920
Total liabilities	2,156,502	2,143,402
Equity:
Common Shares, $.01 par value; 75,000,000 shares authorized; and 65,838,128 and 63,195,182 shares issued at March 31, 2016 and December 31, 2015, respectively	658	632
Preferred shares, $.01 par value; 25,000,000 shares authorized:
Additional paid-in-capital	2,643,605	2,508,445
Treasury shares at cost: 2,496,860 and 2,371,198 common shares at March 31, 2016 and December 31, 2015, respectively	(104,864)	(97,328)
Accumulated other comprehensive income	3,708	5,622
Distributions in excess of net income	(356,208)	(343,642)
Total equity	2,187,038	2,073,868
Total liabilities and equity	4,343,540	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