Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2018	$ 571,535	$ 103,801	$ 467,783	$ (49)
Balance, Shares at Dec. 31, 2018		24,182,000
Net income	18,449		18,449
Share-based compensation	1,392	$ 1,392
Common stock issued under stock Plans, net of shares withheld for employee taxes, Shares		40,000
Taxes paid related to net share settlement of stock awards	(1,555)	$ (1,555)
Dividends accrued of $0.42, and $0.375 per share for three months ended March 31, 2020, and 2019	(9,151)		(9,151)
Other comprehensive gain (loss)	(27)			(27)
Balance at Mar. 31, 2019	580,643	$ 103,638	477,081	(76)
Balance, Shares at Mar. 31, 2019		24,222,000
Balance at Dec. 31, 2019	$ 634,036	$ 106,360	527,746	(70)
Balance, Shares at Dec. 31, 2019	24,296,000	24,296,000
Net income	$ 20,159		20,159
Share-based compensation	1,723	$ 1,723
Common stock issued under stock Plans, net of shares withheld for employee taxes, Shares		50,000
Repurchased common stock	(7,852)	$ (725)	(7,127)
Repurchased common stock, Shares		(164,000)
Taxes paid related to net share settlement of stock awards	(401)	$ (401)
Dividends accrued of $0.42, and $0.375 per share for three months ended March 31, 2020, and 2019	(10,219)		(10,219)
Other comprehensive gain (loss)	158			158
Balance at Mar. 31, 2020	$ 637,604	$ 106,957	$ 530,559	$ 88
Balance, Shares at Mar. 31, 2020	24,182,000	24,182,000