Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings
Beginning balance (in shares) at Dec. 31, 2017		16,267,814
Beginning balance at Dec. 31, 2017	$ 289,406	$ 163	$ 180,674	$ 108,569
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee benefit plans (in shares)		221,890
Issuance of common stock under employee benefit plans	0	$ 2	(2)
Repurchased shares of common and restricted stock from stockholders (in shares)		(65,842)
Deemed repurchased shares of common and restricted stock for tax withholding	(1,815)	$ (1)	(1,814)
Stock-based compensation	6,192		6,192
Net income	16,546			16,546
Ending balance (in shares) at Sep. 30, 2018		16,423,862
Ending balance at Sep. 30, 2018	310,051	$ 164	185,050	124,837
Beginning balance (in shares) at Dec. 31, 2018		16,424,785
Beginning balance at Dec. 31, 2018	321,266	$ 164	187,172	133,930
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock under employee benefit plans (in shares)		252,221
Issuance of common stock under employee benefit plans	0	$ 3	(3)
Repurchased shares of common and restricted stock from stockholders (in shares)		(83,214)
Deemed repurchased shares of common and restricted stock for tax withholding	(2,510)	$ (1)	(2,509)
Stock-based compensation	5,031		5,031
Repurchased and retired shares of common stock (in shares)		(966,081)
Repurchased and retired shares of common stock	(27,303)	$ (10)		(27,293)
Net income	4,294			4,294
Ending balance (in shares) at Sep. 30, 2019		15,627,711
Ending balance at Sep. 30, 2019	$ 300,778	$ 156	$ 189,691	$ 110,931