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] Distributions in excess of net income [Member]	Series G Preferred Stock [Member]	Series G Preferred Stock [Member] Distributions in excess of net income [Member]	Performance Shares [Member]	Performance Shares [Member] Distributions in excess of net income [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
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	3,177			3,177
share based compensation included in severance expense	103			103
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)
Common Stock, Dividends, Per Share, Cash Paid	$ 1.125
Dividends to common and preferred shareholders	$ (84,343)						(84,343)	$ (1,939)	$ (1,939)	$ (1,939)	$ (1,939)	$ (2,156)	$ (2,156)
Preferred Stock, Dividends, Per Share, Cash Paid								$ 0.359375		$ 0.5625		$ 0.359375
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	5,515
Net income	165,946
Balance (in shares) at Sep. 30, 2019		81,365,094	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			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)
Common Stock, Dividends, Per Share, Cash Paid	$ 1.125
Dividends to common and preferred shareholders	$ (86,097)						(86,097)	$ (1,939)	(1,939)	$ (1,939)	(1,939)	$ (2,156)	(2,156)
Preferred Stock, Dividends, Per Share, Cash Paid								$ 0.359375		$ 0.5625		$ 0.359375
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)
Treasury Stock, Retired, Cost Method, Amount	(192)				(192)
Employee Service Share Based Compensation Restricted Stock Units And Restricted Shares Unrecognized Compensation Cost On Nonvested Awards	3,372			3,372
share based compensation included in severance expense	418			418
Foreign currency translation adjustment	(2,267)					(2,267)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	1,752					1,752
Net income	34,003						34,003
Issuances of common shares (in shares)		685,588
Issuances of common shares	52,356	$ 6		52,350
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		1,773
Stock Issued During Period, Value, Stock Options Exercised	$ 0	$ 0		(100)	(100)
Common Stock, Dividends, Per Share, Cash Paid	$ 1.125
Dividends to common and preferred shareholders	$ (87,507)						(87,507)	$ (1,939)	(1,939)	$ (1,939)	(1,939)	$ (2,156)	(2,156)
Preferred Stock, Dividends, Per Share, Cash Paid								$ 0.359375		$ 0.5625		$ 0.359375
Balance (in shares) at Sep. 30, 2019		81,365,094	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	3,040,799	$ 813	$ 148	3,814,465	(147,435)	4,659	(631,851)
Financing Receivable, Allowance for Credit Loss	0
Total equity	3,005,805	$ 816	$ 148	3,834,858	(147,435)	7,275	(689,857)
Balance (in shares) at Dec. 31, 2019		81,588,489	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		211,549
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	6,133	$ 2		6,221	(90)
Treasury Stock, Retired, Cost Method, Amount	(6,769)				(6,769)
Employee Service Share Based Compensation Restricted Stock Units And Restricted Shares Unrecognized Compensation Cost On Nonvested Awards	3,509			3,509
Foreign currency translation adjustment	(16,495)					(16,495)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	3,931					3,931
Net income	37,118						37,118
Issuances of common shares (in shares)		10,368
Issuances of common shares	442	$ 0		442
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		1,410
Stock Issued During Period, Value, Stock Options Exercised	$ 0	$ 0		(63)	(63)
Common Stock, Dividends, Per Share, Cash Paid	$ 1.1325
Dividends to common and preferred shareholders	$ (88,996)						(88,996)	$ (1,939)	(1,939)	$ (1,939)	(1,939)	$ (2,156)	(2,156)
Preferred Stock, Dividends, Per Share, Cash Paid								$ 0.359375		$ 0.5625		$ 0.359375
Balance (in shares) at Mar. 31, 2020		81,811,816	14,841,431
Balance (in shares) at Dec. 31, 2019		81,588,489	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	(5,063)
Net income	$ (111,751)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	1,410
Balance (in shares) at Sep. 30, 2020		81,908,330	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	$ 2,936,481	$ 818	$ 148	3,845,093	(154,357)	(5,289)	(749,932)
Balance (in shares) at Mar. 31, 2020		81,811,816	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, Other		74,767
Stock Issued During Period, Value, Other	1	$ 1
Employee Service Share Based Compensation Restricted Stock Units And Restricted Shares Unrecognized Compensation Cost On Nonvested Awards	3,463			3,463
Foreign currency translation adjustment	7,284					7,284
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(6,326)					(6,326)
Net income	(62,965)						(62,965)
Issuances of common shares (in shares)		17,203
Issuances of common shares	428	$ 0		428
Stock Repurchased During Period, Value	$ (105,994)				105,994
Common Stock, Dividends, Per Share, Cash Paid	$ 0.3825
Dividends to common and preferred shareholders	$ (30,062)						(30,062)	$ (1,939)	(1,939)	$ (1,939)	(1,939)	$ (2,156)	(2,156)	$ (19)	$ (19)
Preferred Stock, Dividends, Per Share, Cash Paid								$ 0.359375		$ 0.5625		$ 0.359375
Balance (in shares) at Jun. 30, 2020		81,903,786	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	2,736,257	$ 819	$ 148	3,848,984	(260,351)	(4,331)	(849,012)
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	0			220	(220)
Treasury Stock, Retired, Cost Method, Amount	(23)				(23)
Employee Service Share Based Compensation Restricted Stock Units And Restricted Shares Unrecognized Compensation Cost On Nonvested Awards	3,410			3,410
Foreign currency translation adjustment	4,148					4,148
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax	(1,923)					(1,923)
Net income	(85,904)						(85,904)
Issuances of common shares (in shares)		4,544
Issuances of common shares	148	$ 0		148
Dividends to common and preferred shareholders								$ (1,939)	$ (1,939)	$ (1,939)	$ (1,939)	$ (2,156)	$ (2,156)	$ (10)	$ (10)
Preferred Stock, Dividends, Per Share, Cash Paid								$ 0.359375		$ 0.5625		$ 0.359375
Balance (in shares) at Sep. 30, 2020		81,908,330	14,841,431
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total equity	2,650,069	$ 819	$ 148	$ 3,852,762	$ (260,594)	$ (2,106)	$ (940,960)
Financing Receivable, Allowance for Credit Loss	$ (12,546)