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 C Preferred Shares [Member]	Series C Preferred Shares [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 G Preferred Stock [Member]	Series G Preferred Stock [Member] Distributions in excess of net income [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	$ 2,927,325	$ 769	$ 148	$ 3,478,986	$ (121,591)	$ 12,483	$ (443,470)
Balance (in shares) at Dec. 31, 2017		76,858,632	14,848,165
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		295,202
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	3,974	$ 3		3,971	0
Treasury Stock, Retired, Cost Method, Amount	(7,116)				(7,116)
Employee Service Share Based Compensation Restricted Stock Units And Restricted Shares Unrecognized Compensation Cost On Nonvested Awards	3,791			3,791
Foreign currency translation adjustment	(5,400)					(5,400)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	9,398					9,398
Net income	29,538						29,538
Issuances of common shares (in shares)		6,601
Issuances of common shares	382	$ 0		382
Stock Issued During Period, Shares, Conversion of Convertible Securities											800
Stock Redeemed or Called During Period, Shares												(1,734)
Stock Redeemed or Called During Period, Value	0											$ 0
Dividends to common and preferred shareholders	(80,263)						(80,263)	$ (1,940)	$ (1,940)	$ (1,939)			$ (1,939)	$ (2,156)	$ (2,156)
Balance (in shares) at Mar. 31, 2018		77,161,235	14,846,431
Balance (in shares) at Dec. 31, 2017		76,858,632	14,848,165
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	(9,468)
Net income	121,119
Balance (in shares) at Jun. 30, 2018		77,195,820	14,846,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	2,875,594	$ 772	$ 148	3,487,130	(128,707)	16,481	(500,230)
Balance (in shares) at Mar. 31, 2018		77,161,235	14,846,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, Other		23,571
Stock Issued During Period, Value, Other	0
Treasury Stock, Retired, Cost Method, Amount	(39)				(39)
Employee Service Share Based Compensation Restricted Stock Units And Restricted Shares Unrecognized Compensation Cost On Nonvested Awards	3,818			3,818
Foreign currency translation adjustment	(4,068)					(4,068)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	5,084					5,084
Net income	91,581						91,581
Issuances of common shares (in shares)		5,272
Issuances of common shares	311	$ 0		311
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		5,742
Stock Issued During Period, Value, Stock Options Exercised	0	$ 0		302	(302)
Dividends to common and preferred shareholders	(80,278)						(80,278)	(1,940)	(1,940)	(1,939)			(1,939)	(2,156)	(2,156)
Balance (in shares) at Jun. 30, 2018		77,195,820	14,846,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	2,885,968	$ 772	$ 148	3,491,561	(129,048)	17,497	(494,962)
Total equity	2,865,023	$ 772	$ 148	3,504,494	(130,728)	12,085	(521,748)
Balance (in shares) at Dec. 31, 2018		77,226,443	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, Other		1,156
Stock Issued During Period, Value, Other	0
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		197,755
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	4,430	$ 2		4,831	(403)
Treasury Stock, Retired, Cost Method, Amount	(9,499)				(9,499)
Employee Service Share Based Compensation Restricted Stock Units And Restricted Shares Unrecognized Compensation Cost On Nonvested Awards	3,280			3,280
Foreign currency translation adjustment	3,810					3,810
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(7,498)					(7,498)
Net income	65,349						65,349
Issuances of common shares (in shares)		1,064,600
Issuances of common shares	78,993	$ 11		78,982
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		111,815
Stock Issued During Period, Value, Stock Options Exercised	(732)	$ 1		5,543	(6,276)
Dividends to common and preferred shareholders	(84,343)						(84,343)	(1,939)	(1,939)	(1,939)			(1,939)	(2,156)	(2,156)
Balance (in shares) at Mar. 31, 2019		78,601,769	14,841,431
Balance (in shares) at Dec. 31, 2018		77,226,443	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	7,782
Net income	$ 131,943
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	117,013
Balance (in shares) at Jun. 30, 2019		80,677,733	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	$ 2,912,779	$ 786	$ 148	3,597,130	(146,906)	8,397	(546,776)
Balance (in shares) at Mar. 31, 2019		78,601,769	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, Other		26,236
Stock Issued During Period, Value, Other	0
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		11,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	0	$ 0		95	(95)
Employee Service Share Based Compensation Restricted Stock Units And Restricted Shares Unrecognized Compensation Cost On Nonvested Awards	3,283			3,283
Foreign currency translation adjustment	3,972					3,972
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(7,195)					(7,195)
Net income	66,594						66,594
Issuances of common shares (in shares)		2,033,530
Issuances of common shares	157,596	$ 21		157,575
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		5,198
Stock Issued During Period, Value, Stock Options Exercised	0	$ 0		142	(142)
Dividends to common and preferred shareholders	(86,097)						(86,097)	$ (1,939)	$ (1,939)	$ (1,939)			$ (1,939)	$ (2,156)	$ (2,156)
Balance (in shares) at Jun. 30, 2019		80,677,733	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	$ 3,044,898	$ 807	$ 148	$ 3,758,225	$ (147,143)	$ 5,174	$ (572,313)