UNAUDITED CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS’ EQUITY (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Income tax expense	$ 7,017				$ 5,374
Dividend (in dollars per share)	$ 0.20	$ 0.20	$ 0.20			$ 0.18	$ 0.18
Tax benefit	$ 40	$ 160	$ 384	$ 37	162		$ 95
Stockholders' Equity Attributable to Parent	170,206	152,476	153,399	167,263	187,925	$ 214,856	178,572
Net income	18,763	9,885	9,106		14,940	74,859	26,855
Issuance for stock-based compensation and dividends, net of forfeitures	0	0	0		0	0	0
Stock-based compensation expense	2,908	2,903	2,896		2,419	3,524	2,620
Employee stock purchase plan	135	134	142		144	143	140
Dividends, Common Stock	(4,164)	(4,162)	(4,293)		(4,043)	(4,278)	(4,406)
Change in fair value of interest rate swaps, net of tax	118	(470)	(1,121)		(113)	(478)	(280)
Treasury Stock, Value, Acquired, Cost Method	(30)	(9,213)	(20,380)		(40,278)	(37,486)	(14,688)
Retained Earnings
Stockholders' Equity Attributable to Parent	374,767	360,409	354,926	350,545	340,436	329,760	259,356
Net income	18,763	9,885	9,106		14,940	74,859	26,855
Issuance for stock-based compensation and dividends, net of forfeitures	(241)	(240)	(218)		(221)	(177)	(233)
Dividends, Common Stock	$ (4,164)	$ (4,162)	(4,293)		$ (4,043)	$ (4,278)	$ (4,406)
Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity Attributable to Parent				(214)
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings
Income tax expense			$ 75
Stockholders' Equity Attributable to Parent				$ (214)