Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Total stockholders' equity	Noncontrolling Interests
Balance, Value at Dec. 31, 2017	$ 3,483,025	$ 1	$ 2,236,351	$ 1,311,112	$ (67,509)	$ 3,479,955	$ 3,070
Balance, Shares at Dec. 31, 2017		110,925
Cumulative-effect adjustment | Accounting Standards Update 2016-01				40,550	(40,550)
Net income (loss)	76,172			76,227		76,227	(55)
Dividends on common shares	(42,330)			(42,330)		(42,330)
Shares issued in connection with share-based compensation, value	(12,606)		(11,759)	(847)		(12,606)
Shares issued in connection with share-based compensation, shares		620
Share-based compensation	19,509		19,509			19,509
Net activity related to noncontrolling interests	(901)		189			189	(1,090)
Other comprehensive income (loss)	(50,428)				(50,409)	(50,409)	(19)
Balance, Value at Mar. 31, 2018	3,472,441	$ 1	2,244,290	1,384,712	(158,468)	3,470,535	1,906
Balance, Shares at Mar. 31, 2018		111,545
Balance, Value at Dec. 31, 2017	3,483,025	$ 1	2,236,351	1,311,112	(67,509)	3,479,955	3,070
Balance, Shares at Dec. 31, 2017		110,925
Net income (loss)	231,263
Other comprehensive income (loss)	(73,329)
Balance, Value at Jun. 30, 2018	3,571,222	$ 1	2,254,253	1,496,638	(181,369)	3,569,523	1,699
Balance, Shares at Jun. 30, 2018		111,658
Balance, Value at Mar. 31, 2018	3,472,441	$ 1	2,244,290	1,384,712	(158,468)	3,470,535	1,906
Balance, Shares at Mar. 31, 2018		111,545
Net income (loss)	155,091			155,140		155,140	(49)
Dividends on common shares	(42,387)			(42,387)		(42,387)
Shares issued in connection with share-based compensation, value	1,377		2,204	(827)		1,377
Shares issued in connection with share-based compensation, shares		113
Share-based compensation	7,626		7,626			7,626
Net activity related to noncontrolling interests	(25)		133			133	(158)
Other comprehensive income (loss)	(22,901)				(22,901)	(22,901)
Balance, Value at Jun. 30, 2018	3,571,222	$ 1	2,254,253	1,496,638	(181,369)	3,569,523	1,699
Balance, Shares at Jun. 30, 2018		111,658
Balance, Value at Dec. 31, 2018	$ 3,745,388	$ 1	2,258,290	1,644,165	(160,575)	3,741,881	3,507
Balance, Shares at Dec. 31, 2018	111,496	111,496
Cumulative-effect adjustment | Accounting Standards Update 2016-02	$ 1,283			1,283		1,283
Net income (loss)	109,804			109,575		109,575	229
Dividends on common shares	(47,021)			(47,021)		(47,021)
Purchase of Company shares	(2,066)		(2,066)			(2,066)
Purchase of Company shares, shares		(47)
Shares issued in connection with share-based compensation, value	(11,480)		(10,618)	(862)		(11,480)
Shares issued in connection with share-based compensation, shares		623
Share-based compensation	19,597		19,597			19,597
Net activity related to noncontrolling interests	(1,286)		(60)			(60)	(1,226)
Other comprehensive income (loss)	66,317				66,318	66,318	(1)
Balance, Value at Mar. 31, 2019	3,880,536	$ 1	2,265,143	1,707,140	(94,257)	3,878,027	2,509
Balance, Shares at Mar. 31, 2019		112,072
Balance, Value at Dec. 31, 2018	$ 3,745,388	$ 1	2,258,290	1,644,165	(160,575)	3,741,881	3,507
Balance, Shares at Dec. 31, 2018	111,496	111,496
Net income (loss)	$ 297,075
Other comprehensive income (loss)	122,860
Balance, Value at Jun. 30, 2019	$ 4,088,034	$ 1	2,276,737	1,845,865	(37,714)	4,084,889	3,145
Balance, Shares at Jun. 30, 2019	112,217	112,217
Balance, Value at Mar. 31, 2019	$ 3,880,536	$ 1	2,265,143	1,707,140	(94,257)	3,878,027	2,509
Balance, Shares at Mar. 31, 2019		112,072
Net income (loss)	187,271			186,655		186,655	616
Dividends on common shares	(47,084)			(47,084)		(47,084)
Shares issued in connection with share-based compensation, value	2,990		3,836	(846)		2,990
Shares issued in connection with share-based compensation, shares		145
Share-based compensation	7,758		7,758			7,758
Net activity related to noncontrolling interests	20						20
Other comprehensive income (loss)	56,543				56,543	56,543
Balance, Value at Jun. 30, 2019	$ 4,088,034	$ 1	$ 2,276,737	$ 1,845,865	$ (37,714)	$ 4,084,889	$ 3,145
Balance, Shares at Jun. 30, 2019	112,217	112,217