CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Retained Earnings	Treasury Stock
Balance (in shares) at Dec. 31, 2020		11,822
Balance at Dec. 31, 2020	$ 157,246	$ 12	$ 7,842	$ 41	$ 154,351	$ (5,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	41,063				41,063
Share-based compensation (in shares)		13
Share-based compensation	2,198		2,198
Options exercised by executives and directors (in shares)		11
Options exercised by executives and directors	481		481
Net shares repurchased for taxes (in shares)		(7)
Net shares repurchased for taxes	(1,807)		(1,807)
Treasury stock from stock repurchases	(7,500)					(7,500)
Other comprehensive Income (loss)	62			62
Cash dividends declared to stockholders	(16,852)				(16,852)
Balance (in shares) at Mar. 31, 2021		11,839
Balance at Mar. 31, 2021	174,891	$ 12	8,714	103	178,562	(12,500)
Balance (in shares) at Dec. 31, 2020		11,822
Balance at Dec. 31, 2020	157,246	$ 12	7,842	41	154,351	(5,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 130,008
Options exercised by executives and directors (in shares)	16
Net shares repurchased for taxes (in shares)	(7)
Other comprehensive Income (loss)	$ 81
Balance (in shares) at Sep. 30, 2021		11,618
Balance at Sep. 30, 2021	196,239	$ 12	12,950	122	183,155	0
Balance (in shares) at Mar. 31, 2021		11,839
Balance at Mar. 31, 2021	174,891	$ 12	8,714	103	178,562	(12,500)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	46,963				46,963
Share-based compensation (in shares)		10
Share-based compensation	1,839		1,697		142
Options exercised by executives and directors (in shares)		3
Options exercised by executives and directors	221		221
Net shares repurchased for taxes	(26)		(26)
Treasury stock from stock repurchases	(12,230)					(12,230)
Treasury stock retired from stock repurchases (in shares)		(114)
Treasury stock retired from stock repurchases	0				(23,383)	23,383
Other comprehensive Income (loss)	(28)			(28)
Cash dividends declared to stockholders	(16,941)				(16,941)
Balance (in shares) at Jun. 30, 2021		11,738
Balance at Jun. 30, 2021	194,689	$ 12	10,606	75	185,343	(1,347)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	41,982				41,982
Share-based compensation (in shares)		1
Share-based compensation	2,269		2,269
Options exercised by executives and directors (in shares)		3
Options exercised by executives and directors	109		109
Net shares repurchased for taxes (in shares)		(1)
Net shares repurchased for taxes	(34)		(34)
Treasury stock from stock repurchases	(26,270)					(26,270)
Treasury stock retired from stock repurchases (in shares)		(123)
Treasury stock retired from stock repurchases					(27,617)	27,617
Other comprehensive Income (loss)	47			47
Cash dividends declared to stockholders	(16,553)				(16,553)
Balance (in shares) at Sep. 30, 2021		11,618
Balance at Sep. 30, 2021	$ 196,239	$ 12	12,950	122	183,155	0
Balance (in shares) at Dec. 31, 2021	11,594	11,594
Balance at Dec. 31, 2021	$ 202,474	$ 12	12,018	111	190,333	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	41,781				41,781
Share-based compensation (in shares)		18
Share-based compensation	2,275		2,275
Net shares repurchased for taxes (in shares)		(8)
Net shares repurchased for taxes	(1,459)		(1,459)
Treasury stock from stock repurchases	(10,000)					(10,000)
Treasury stock retired from stock repurchases (in shares)		(51)
Treasury stock retired from stock repurchases	0				(10,000)	10,000
Other comprehensive Income (loss)	16			16
Cash dividends declared to stockholders	(19,063)				(19,063)
Balance (in shares) at Mar. 31, 2022		11,553
Balance at Mar. 31, 2022	$ 216,024	$ 12	12,834	127	203,051	0
Balance (in shares) at Dec. 31, 2021	11,594	11,594
Balance at Dec. 31, 2021	$ 202,474	$ 12	12,018	111	190,333	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 117,050
Options exercised by executives and directors (in shares)	0
Net shares repurchased for taxes (in shares)	(8)
Other comprehensive Income (loss)	$ 279
Balance (in shares) at Sep. 30, 2022	10,929	10,929
Balance at Sep. 30, 2022	$ 150,522	$ 11	18,617	391	131,503	0
Balance (in shares) at Mar. 31, 2022		11,553
Balance at Mar. 31, 2022	216,024	$ 12	12,834	127	203,051	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	39,113				39,113
Share-based compensation (in shares)		1
Share-based compensation	2,865		2,865
Net shares repurchased for taxes	(20)		(20)
Treasury stock from stock repurchases	(90,038)					(90,038)
Treasury stock retired from stock repurchases (in shares)		(535)
Treasury stock retired from stock repurchases	(1)	$ (1)			(90,038)	90,038
Stock repurchases, not yet settled	(20,010)		(15,679)		(4,331)
Other comprehensive Income (loss)	141			141
Cash dividends declared to stockholders	(18,598)				(18,598)
Balance (in shares) at Jun. 30, 2022		11,019
Balance at Jun. 30, 2022	129,476	$ 11	0	268	129,197	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	36,155				36,155
Share-based compensation (in shares)		1
Share-based compensation	2,963		2,963
Net shares repurchased for taxes	(25)		(25)			0
Treasury stock from stock repurchases	(20,010)					(20,010)
Treasury stock retired from stock repurchases (in shares)		(91)
Treasury stock retired from stock repurchases	0				(20,010)	20,010
Settlement of accelerated share repurchase agreement	20,010		15,679		4,331
Other comprehensive Income (loss)	123			123
Cash dividends declared to stockholders	$ (18,170)				(18,170)
Balance (in shares) at Sep. 30, 2022	10,929	10,929
Balance at Sep. 30, 2022	$ 150,522	$ 11	$ 18,617	$ 391	$ 131,503	$ 0