Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common stock	Other paid-in capital	Retained earnings	Accumulated other comprehensive loss	Treasury stock
Common stock balance (in shares) at Dec. 31, 2018		196,564,907
Treasury stock (in shares) at Dec. 31, 2018						(538,921)
Balance at Dec. 31, 2018	$ 2,566,775	$ 196,565	$ 1,248,576	$ 1,163,602	$ (38,342)	$ (3,626)
Net income	40,926			40,926
Other comprehensive income	774				774
Dividends declared on common stock	(40,019)			(40,019)
Stock-based compensation	1,617		1,617
Issuance of common stock upon vesting of stock-based compensation, tax withholding shares		246,214
Issuance of common stock upon vesting of stock-based compensation, tax withholding shares value		$ 246
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings			(3,261)
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings	(3,015)
Issuance of common stock (shares)		1,505,687
Issuance of common stock	38,634	$ 1,506	37,128
Common stock balance (in shares) at Mar. 31, 2019		198,316,808
Treasury stock (in shares) at Mar. 31, 2019						(538,921)
Balance at Mar. 31, 2019	2,605,692	$ 198,317	1,284,060	1,164,509	(37,568)	$ (3,626)
Common stock balance (in shares) at Dec. 31, 2018		196,564,907
Treasury stock (in shares) at Dec. 31, 2018						(538,921)
Balance at Dec. 31, 2018	2,566,775	$ 196,565	1,248,576	1,163,602	(38,342)	$ (3,626)
Net income	240,388
Other comprehensive income	1,664
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings	$ (3,015)
Common stock balance (in shares) at Sep. 30, 2019	200,876,334	200,876,334
Treasury stock (in shares) at Sep. 30, 2019						(538,921)
Balance at Sep. 30, 2019	$ 2,795,606	$ 200,876	1,351,990	1,283,044	(36,678)	$ (3,626)
Common stock balance (in shares) at Mar. 31, 2019		198,316,808
Treasury stock (in shares) at Mar. 31, 2019						(538,921)
Balance at Mar. 31, 2019	2,605,692	$ 198,317	1,284,060	1,164,509	(37,568)	$ (3,626)
Net income	61,825			61,825
Other comprehensive income	478				478
Dividends declared on common stock	(40,367)			(40,367)
Stock-based compensation	1,742		1,742
Issuance of common stock (shares)		1,222,302
Issuance of common stock	30,931	$ 1,222	29,709
Common stock balance (in shares) at Jun. 30, 2019		199,539,110
Treasury stock (in shares) at Jun. 30, 2019						(538,921)
Balance at Jun. 30, 2019	2,660,301	$ 199,539	1,315,511	1,185,967	(37,090)	$ (3,626)
Net income	137,637			137,637
Other comprehensive income	412				412
Dividends declared on common stock	(40,560)			(40,560)
Stock-based compensation	1,742		1,742
Issuance of common stock (shares)		1,337,224
Issuance of common stock	$ 36,074	$ 1,337	34,737
Common stock balance (in shares) at Sep. 30, 2019	200,876,334	200,876,334
Treasury stock (in shares) at Sep. 30, 2019						(538,921)
Balance at Sep. 30, 2019	$ 2,795,606	$ 200,876	1,351,990	1,283,044	(36,678)	$ (3,626)
Common stock balance (in shares) at Dec. 31, 2019	200,922,790	200,922,790
Treasury stock (in shares) at Dec. 31, 2019						(538,921)
Balance at Dec. 31, 2019	$ 2,847,246	$ 200,923	1,355,404	1,336,647	(42,102)	$ (3,626)
Net income	25,130			25,130
Other comprehensive income	707				707
Dividends declared on common stock	(41,789)			(41,789)
Stock-based compensation	2,250		2,250
Issuance of common stock upon vesting of stock-based compensation, tax withholding shares		26,406
Issuance of common stock upon vesting of stock-based compensation, tax withholding shares value		$ 26
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings			(388)
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings	(362)
Issuance of common stock (shares)		112,002
Issuance of common stock	3,410	$ 112	3,298
Common stock balance (in shares) at Mar. 31, 2020		201,061,198
Treasury stock (in shares) at Mar. 31, 2020						(538,921)
Balance at Mar. 31, 2020	$ 2,836,592	$ 201,061	1,360,564	1,319,988	(41,395)	$ (3,626)
Common stock balance (in shares) at Dec. 31, 2019	200,922,790	200,922,790
Treasury stock (in shares) at Dec. 31, 2019						(538,921)
Balance at Dec. 31, 2019	$ 2,847,246	$ 200,923	1,355,404	1,336,647	(42,102)	$ (3,626)
Net income	277,911
Other comprehensive income	1,853
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings	$ (362)
Common stock balance (in shares) at Sep. 30, 2020	201,061,198	201,061,198
Treasury stock (in shares) at Sep. 30, 2020						(538,921)
Balance at Sep. 30, 2020	$ 3,012,765	$ 201,061	1,366,494	1,489,085	(40,249)	$ (3,626)
Common stock balance (in shares) at Mar. 31, 2020		201,061,198
Treasury stock (in shares) at Mar. 31, 2020						(538,921)
Balance at Mar. 31, 2020	2,836,592	$ 201,061	1,360,564	1,319,988	(41,395)	$ (3,626)
Net income	99,703			99,703
Other comprehensive income	586				586
Dividends declared on common stock	(41,812)			(41,812)
Stock-based compensation	2,618		2,618
Common stock balance (in shares) at Jun. 30, 2020		201,061,198
Treasury stock (in shares) at Jun. 30, 2020						(538,921)
Balance at Jun. 30, 2020	2,897,687	$ 201,061	1,363,182	1,377,879	(40,809)	$ (3,626)
Net income	153,078			153,078
Other comprehensive income	560				560
Dividends declared on common stock	(41,872)			(41,872)
Stock-based compensation	$ 3,312		3,312
Common stock balance (in shares) at Sep. 30, 2020	201,061,198	201,061,198
Treasury stock (in shares) at Sep. 30, 2020						(538,921)
Balance at Sep. 30, 2020	$ 3,012,765	$ 201,061	$ 1,366,494	$ 1,489,085	$ (40,249)	$ (3,626)