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, 2016					$ (23,417)
Increase (Decrease) in Stockholders' Equity
Net income						$ 8,370
Other comprehensive income, net of tax					1,391	1,391
Balances at Jun. 30, 2017					(22,026)
Increase (Decrease) in Stockholders' Equity
Adjustments to beginning retained earnings for adoption of accounting standards | ASC Topic 606 and ASC Topic 220			$ 3,992		(3,576)	416
Adjusted Balances	$ 285	$ 319,436	442,371	$ (86,064)	(24,150)	651,878
Balances at Dec. 31, 2017	$ 285	319,436	438,379	$ (86,064)	(20,574)	651,462
Balances (in shares) at Dec. 31, 2017	28,496			2,852
Increase (Decrease) in Stockholders' Equity
Net income			11,187			11,187
Other comprehensive income, net of tax					6,308	6,308
Issuance of common stock under share-based compensation plans (in shares)	46
Tax effect of share-based compensation plans		(85)				(85)
Share-based compensation expense		3,544				3,544
Purchase of treasury stock				$ (201)		(201)
Purchase of treasury stock (in shares)				5
Dividends declared on common stock			(4,116)			(4,116)
Balances at Jun. 30, 2018	$ 285	$ 322,895	$ 449,442	$ (86,265)	$ (17,842)	$ 668,515
Balances (in shares) at Jun. 30, 2018	28,542			2,857