Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Total
Balance (in shares) at Dec. 31, 2018	81,700,000
Balance at Dec. 31, 2018	$ 817	$ 76,814	$ 498,323	$ 575,954
Net income	$ 0	0	61,071	61,071
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in shares)	355,000
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards	$ 4	1,618	(2)	1,620
Employee taxes paid in exchange for shares withheld	0	(784)	0	(784)
Share-based payment arrangement compensation expense	0	1,817	0	1,817
Dividends on common stock	$ 0	0	(42,089)	$ (42,089)
Repurchase and retirement of common stock (in shares)				0
Balance (in shares) at Dec. 31, 2019	82,055,000
Balance at Dec. 31, 2019	$ 821	79,465	517,303	$ 597,589
Net income	$ 0	0	69,500	69,500
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in shares)	703
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards	$ 7	4,787	(1)	4,793
Employee taxes paid in exchange for shares withheld	0	(437)	0	(437)
Share-based payment arrangement compensation expense	0	1,851	0	1,851
Dividends on common stock	$ 0	0	(52,366)	$ (52,366)
Repurchase and retirement of common stock (in shares)	(53,000)			0
Repurchase and retirement of common stock	$ (1)	(596)	0	$ (597)
Balance (in shares) at Dec. 31, 2020	82,705,000
Balance at Dec. 31, 2020	$ 827	85,070	534,436	620,333
Net income	$ 0	0	85,428	85,428
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in shares)	329,000
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards	$ 3	873	0	876
Employee taxes paid in exchange for shares withheld	0	(2,743)	0	(2,743)
Share-based payment arrangement compensation expense	0	2,518	0	2,518
Dividends on common stock	$ 0	0	(54,735)	$ (54,735)
Repurchase and retirement of common stock (in shares)				0
Balance (in shares) at Dec. 31, 2021	83,034,000
Balance at Dec. 31, 2021	$ 830	$ 85,718	$ 565,129	$ 651,677