UNAUDITED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Accumulated Earnings
Balance beginning of period (in shares) at Dec. 31, 2019		55,798
Balance beginning of period at Dec. 31, 2019	$ 1,269,813	$ 558	$ 644,412	$ (210,051)	$ 834,894
Increase (Decrease) in Stockholders' Equity
Net income	11,572				11,572
Other comprehensive (loss) income	(59,306)			(59,306)
Stock-based compensation	3,291		3,291
Issuance of common stock for restricted share vesting, net of employee tax withholdings (in shares)		59
Issuance of common stock for restricted share vesting, net of employee tax withholdings	(2,224)	$ 1	(2,225)
Repurchases of common stock (in shares)		(302)
Repurchases of common stock	(17,341)	$ (3)	(17,338)
Balance ending of period (in shares) at Mar. 31, 2020		55,555
Balance ending of period at Mar. 31, 2020	1,205,805	$ 556	628,140	(269,357)	846,466
Balance beginning of period (in shares) at Dec. 31, 2019		55,798
Balance beginning of period at Dec. 31, 2019	1,269,813	$ 558	644,412	(210,051)	834,894
Increase (Decrease) in Stockholders' Equity
Net income	95,505
Other comprehensive (loss) income	(29,393)
Balance ending of period (in shares) at Sep. 30, 2020		55,246
Balance ending of period at Sep. 30, 2020	1,304,715	$ 552	613,208	(239,444)	930,399
Balance beginning of period (in shares) at Mar. 31, 2020		55,555
Balance beginning of period at Mar. 31, 2020	1,205,805	$ 556	628,140	(269,357)	846,466
Increase (Decrease) in Stockholders' Equity
Net income	29,023				29,023
Other comprehensive (loss) income	17,528			17,528
Stock-based compensation	2,786		2,786
Issuance of common stock for restricted share vesting, net of employee tax withholdings (in shares)		58
Issuance of common stock for restricted share vesting, net of employee tax withholdings	(1,171)		(1,171)
Balance ending of period (in shares) at Jun. 30, 2020		55,613
Balance ending of period at Jun. 30, 2020	1,253,971	$ 556	629,755	(251,829)	875,489
Increase (Decrease) in Stockholders' Equity
Net income	54,910				54,910
Other comprehensive (loss) income	12,385			12,385
Stock-based compensation	6,662		6,662
Issuance of common stock for restricted share vesting, net of employee tax withholdings (in shares)		35
Issuance of common stock for restricted share vesting, net of employee tax withholdings	(1,012)		(1,012)
Repurchases of common stock (in shares)		(402)
Repurchases of common stock	(22,201)	$ (4)	(22,197)
Balance ending of period (in shares) at Sep. 30, 2020		55,246
Balance ending of period at Sep. 30, 2020	1,304,715	$ 552	613,208	(239,444)	930,399
Balance beginning of period (in shares) at Dec. 31, 2020		54,773
Balance beginning of period at Dec. 31, 2020	1,341,551	$ 548	582,749	(211,477)	969,731
Increase (Decrease) in Stockholders' Equity
Net income	21,736				21,736
Other comprehensive (loss) income	11,948			11,948
Stock-based compensation	3,480		3,480
Issuance of common stock for restricted share vesting, net of employee tax withholdings (in shares)		78
Issuance of common stock for restricted share vesting, net of employee tax withholdings	(3,719)	$ 1	(3,720)
Repurchases of common stock (in shares)		(300)
Repurchases of common stock	(26,546)	$ (3)	(26,543)
Balance ending of period (in shares) at Mar. 31, 2021		54,551
Balance ending of period at Mar. 31, 2021	1,348,450	$ 546	555,966	(199,529)	991,467
Balance beginning of period (in shares) at Dec. 31, 2020		54,773
Balance beginning of period at Dec. 31, 2020	1,341,551	$ 548	582,749	(211,477)	969,731
Increase (Decrease) in Stockholders' Equity
Net income	154,254
Other comprehensive (loss) income	10,761
Balance ending of period (in shares) at Sep. 30, 2021		54,410
Balance ending of period at Sep. 30, 2021	1,463,560	$ 544	539,747	(200,716)	1,123,985
Balance beginning of period (in shares) at Mar. 31, 2021		54,551
Balance beginning of period at Mar. 31, 2021	1,348,450	$ 546	555,966	(199,529)	991,467
Increase (Decrease) in Stockholders' Equity
Net income	67,075				67,075
Other comprehensive (loss) income	10,640			10,640
Stock-based compensation	3,305		3,305
Issuance of common stock for restricted share vesting, net of employee tax withholdings (in shares)		42
Issuance of common stock for restricted share vesting, net of employee tax withholdings	(1,020)		(1,020)
Repurchases of common stock (in shares)		(200)
Repurchases of common stock	(18,863)	$ (2)	(18,861)
Balance ending of period (in shares) at Jun. 30, 2021		54,393
Balance ending of period at Jun. 30, 2021	1,409,587	$ 544	539,390	(188,889)	1,058,542
Increase (Decrease) in Stockholders' Equity
Net income	65,443				65,443
Other comprehensive (loss) income	(11,827)			(11,827)
Stock-based compensation	6,001		6,001
Issuance of common stock for restricted share vesting, net of employee tax withholdings (in shares)		50
Issuance of common stock for restricted share vesting, net of employee tax withholdings	(2,644)		(2,644)
Repurchases of common stock (in shares)		(33)
Repurchases of common stock	(3,000)	$ 0	(3,000)
Balance ending of period (in shares) at Sep. 30, 2021		54,410
Balance ending of period at Sep. 30, 2021	$ 1,463,560	$ 544	$ 539,747	$ (200,716)	$ 1,123,985