Consolidated Statement Of Changes In Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Preferred Stock [Member]	Additional paid-in capital [Member]	Treasury shares [Member]	Accumulated other comprehensive income (loss) [Member]	Distributions in excess of net income [Member]	Series E Preferred Shares [Member]	Series E Preferred Shares [Member] Common Stock [Member]	Series E Preferred Shares [Member] Preferred Stock [Member]	Series E Preferred Shares [Member] Distributions in excess of net income [Member]	Series C Preferred Shares [Member]	Series C Preferred Shares [Member] Common Stock [Member]	Series C Preferred Shares [Member] Preferred Stock [Member]	Series C Preferred Shares [Member] Distributions in excess of net income [Member]	Series G Preferred Stock [Member]	Series G Preferred Stock [Member] Preferred Stock [Member]	Series G Preferred Stock [Member] Additional paid-in capital [Member]	Series G Preferred Stock [Member] Distributions in excess of net income [Member]	Series F Preferred Stock [Member]	Series F Preferred Stock [Member] Preferred Stock [Member]	Series F Preferred Stock [Member] Additional paid-in capital [Member]	Series F Preferred Stock [Member] Distributions in excess of net income [Member]
Balance (in shares) at Dec. 31, 2016		66,263,487	13,849,050
Balance at Dec. 31, 2016	$ 2,185,901	$ 663	$ 139	$ 2,677,046	$ (113,172)	$ 7,734	$ (386,509)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, Other		19,030
Stock Issued During Period, Value, Other	0
Issuance of nonvested shares, net		296,914
Issuance of nonvested shares, net	5,498	$ 3		5,585	(90)
Treasury Stock, Retired, Cost Method, Amount	(6,729)				(6,729)
Amortization of nonvested shares	(14,142)			(14,142)
Foreign currency translation adjustment	12,569					12,569
Change in unrealized gain/loss on derivatives	(7,820)					(7,820)
Net income	262,968						262,968
Issuances of common shares (in shares)		1,398,280															6,000,000
Issuances of common shares, net of costs	99,336	$ 14		99,322
Stock Issued During Period, Shares, Acquisitions		8,851,264
Stock Issued During Period, Value, Acquisitions	657,473	$ 89		657,384
Stock Issued During Period, Shares, Conversion of Convertible Securities									404
Stock Redeemed or Called During Period, Shares										885											(5,000,000)
Preferred Share Redemption Costs	4,457																						$ (4,457)
Payments for Repurchase of Redeemable Preferred Stock	(125,025)																			$ (125,025)	$ 50	$ 120,518
Stock Redeemed or Called During Period, Value	(1)									$ (1)
Proceeds from Issuance of Preferred Stock and Preference Stock	$ 144,490															$ 144,490	$ 60	$ 144,430
Stock option exercises, net (in shares)	29,253	29,253
Stock option exercises, net	$ (5)	$ 0		1,595	1,600
Dividends to common and preferred shareholders	(291,179)						(291,179)	$ (7,762)			$ (7,762)	$ (7,761)			$ (7,761)	$ (719)			$ (719)	$ (8,051)			$ (8,051)
Balance (in shares) at Dec. 31, 2017		76,858,632	14,848,165
Balance at Dec. 31, 2017	$ 2,927,325	$ 769	$ 148	3,478,986	(121,591)	12,483	(443,470)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends, Per Share, Cash Paid	$ 4.08
Preferred Stock, Dividends, Per Share, Cash Paid								$ 2.25				$ 1.4375				$ 0.183681				$ 1.9553
Stock Issued During Period, Shares, Other		23,571
Stock Issued During Period, Value, Other	$ 0
Issuance of nonvested shares, net		295,202
Issuance of nonvested shares, net	3,974	$ 3		4,588	(617)
Treasury Stock, Retired, Cost Method, Amount	(7,156)				(7,156)
Amortization of nonvested shares	(15,111)			(15,111)
share based compensation included in severance expense	3,218			3,218
Foreign currency translation adjustment	(16,177)					(16,177)
Change in unrealized gain/loss on derivatives	15,779					15,779
Net income	266,983						266,983
Issuances of common shares (in shares)		20,553
Issuances of common shares, net of costs	1,286	$ 0		1,286
Stock Issued During Period, Value, Acquisitions	0
Stock Issued During Period, Shares, Conversion of Convertible Securities									800				1,964
Stock Redeemed or Called During Period, Shares										1,734				(5,000)
Preferred Share Redemption Costs	0
Payments for Repurchase of Redeemable Preferred Stock	0
Stock Issued During Period, Value, Conversion of Convertible Securities	0
Stock Redeemed or Called During Period, Value	0									$ 0
Proceeds from Issuance of Preferred Stock and Preference Stock	$ 0
Stock option exercises, net (in shares)	25,721	25,721
Stock option exercises, net	$ (59)	$ 0		1,305	1,364
Dividends to common and preferred shareholders	(321,119)						(321,119)	$ (7,757)			(7,757)	$ (7,760)			(7,760)	$ (8,625)			(8,625)
Balance (in shares) at Dec. 31, 2018		77,226,443	14,841,431
Balance at Dec. 31, 2018	$ 2,865,023	$ 772	$ 148	3,504,494	(130,728)	12,085	(521,748)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends, Per Share, Cash Paid	$ 4.32
Preferred Stock, Dividends, Per Share, Cash Paid								$ 2.25				$ 1.4375				$ 1.4375				0
Stock Issued During Period, Shares, Other		27,392
Stock Issued During Period, Value, Other	$ 0
Issuance of nonvested shares, net		208,755
Issuance of nonvested shares, net	4,430	$ 2		4,926	(498)
Treasury Stock, Retired, Cost Method, Amount	(9,691)				(9,691)
Amortization of nonvested shares	(13,180)			(13,180)
share based compensation included in severance expense	580			580
Foreign currency translation adjustment	9,253					9,253
Change in unrealized gain/loss on derivatives	(14,063)					(14,063)
Net income	202,243						202,243
Issuances of common shares (in shares)		4,007,113
Issuances of common shares, net of costs	305,934	$ 41		305,893
Stock Issued During Period, Value, Acquisitions	0
Preferred Share Redemption Costs	0
Payments for Repurchase of Redeemable Preferred Stock	0
Proceeds from Issuance of Preferred Stock and Preference Stock	$ 0
Stock option exercises, net (in shares)	118,786	118,786
Stock option exercises, net	$ (732)	$ 1		5,785	6,518
Dividends to common and preferred shareholders	(346,216)						(346,216)	$ (7,756)			$ (7,756)	$ (7,756)			$ (7,756)	$ (8,624)			$ (8,624)
Balance (in shares) at Dec. 31, 2019		81,588,489	14,841,431
Balance at Dec. 31, 2019	$ 3,005,805	$ 816	$ 148	$ 3,834,858	$ (147,435)	$ 7,275	$ (689,857)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common Stock, Dividends, Per Share, Cash Paid	$ 4.50
Preferred Stock, Dividends, Per Share, Cash Paid								$ 2.25				$ 1.4375				$ 1.4375				$ 0