CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss	Total
Balances at Dec. 31, 2015					$ (27,496)
Increase (Decrease) in Stockholders' Equity
Net income						$ 17,068
Other comprehensive income, net of tax					(943)	(943)
Balances at Sep. 30, 2016					(28,439)
Balances at Dec. 31, 2016	$ 282	$ 315,318	$ 386,917	$ (80,045)	(23,417)	599,055
Balances (in shares) at Dec. 31, 2016	28,174			2,565
Increase (Decrease) in Stockholders' Equity
Net income			23,158			23,158
Other comprehensive income, net of tax					1,216	1,216
Issuance of common stock under share-based compensation plans	$ 3	(3)
Issuance of common stock under share-based compensation plans (in shares)	304
Tax effect of share-based compensation plans		(2,708)				(2,708)
Share-based compensation expense		5,070				5,070
Purchase of treasury stock				$ (6,019)		(6,019)
Purchase of treasury stock (in shares)				287
Dividends declared on common stock			(6,207)			(6,207)
Balances at Sep. 30, 2017	$ 285	$ 317,677	$ 403,868	$ (86,064)	$ (22,201)	$ 613,565
Balances (in shares) at Sep. 30, 2017	28,478			2,852