Consolidated Balance Sheets - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Document Period End Date	Jun. 30, 2019
Assets
Real estate investments, net of accumulated depreciation of $954,806 and $883,174 at June 30, 2019 and December 31, 2018, respectively	$ 5,598,246	$ 5,024,057
Land held for development	28,080	34,177
Property under development	80,695	287,546
Operating Lease, Right-of-Use Asset	220,758	0
Mortgage notes and related accrued interest receivable	550,131	517,467
Investment in direct financing leases, net	20,675	20,558
Investment in joint ventures	35,658	34,486
Cash and cash equivalents	6,927	5,872
Restricted cash	5,010	12,635
Accounts receivable, net	108,433	98,369
Other assets	92,042	96,223
Total assets	6,746,655	6,131,390
Liabilities:
Accounts payable and accrued liabilities	126,015	168,463
Operating Lease, Liability	245,372	0
Dividends Payable, Current	29,084	26,765
Preferred dividends payable	6,034	6,034
Unearned rents and interest	78,629	79,051
Debt	3,216,623	2,986,054
Total liabilities	3,701,757	3,266,367
Equity:
Common Shares, $.01 par value; 100,000,000 shares authorized; and 80,677,733 and 77,226,443 shares issued at June 30, 2019 and December 31, 2018, respectively	807	772
Preferred shares, $.01 par value; 25,000,000 shares authorized:
Additional paid-in-capital	3,758,225	3,504,494
Treasury shares at cost: 3,121,730 and 2,878,587 common shares at June 30, 2019 and December 31, 2018, respectively	(147,143)	(130,728)
Accumulated other comprehensive income	5,174	12,085
Distributions in excess of net income	572,313	521,748
Total equity	3,044,898	2,865,023
Total liabilities and equity	6,746,655	6,131,390
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	34	34
Series G Preferred Stock [Member]
Preferred shares, $.01 par value; 25,000,000 shares authorized:
Preferred shares	$ 60	$ 60