CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Capital in Excess of Par Value	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Treasury Stock
Beginning Balance (in shares) at Dec. 31, 2012		23,785
Beginning Balance at Dec. 31, 2012	$ 174,496	$ 2,379	$ 58,784	$ 201,097	$ (18,366)	$ (69,398)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,155			19,155
Other comprehensive income (loss), net of tax	9,522				9,522
Stock repurchased	(6,617)					(6,617)
Stock issued under employee plans (in shares)		297
Stock issued under employee plans	1,497	$ 30	1,467
Excess tax benefit on stock awards	271		271
Stock based compensation expense	1,511		1,511
Stock issued to directors (in shares)		16
Stock issued to directors	252	$ 1	251
Ending Balance (in shares) at Dec. 31, 2013		24,098
Ending Balance at Dec. 31, 2013	200,087	$ 2,410	62,284	220,252	(8,844)	(76,015)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	21,847			21,847
Other comprehensive income (loss), net of tax	(15,317)				(15,317)
Stock repurchased	(748)					(748)
Stock issued under employee plans (in shares)		524
Stock issued under employee plans	2,457	$ 52	2,405
Excess tax benefit on stock awards	1,486		1,486
Stock based compensation expense	2,535		2,535
Stock issued to directors (in shares)		9
Stock issued to directors	$ 252	$ 1	251
Ending Balance (in shares) at Dec. 31, 2014	24,631	24,631
Ending Balance at Dec. 31, 2014	$ 212,599	$ 2,463	68,961	242,099	(24,161)	(76,763)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	46,259			46,259
Other comprehensive income (loss), net of tax	(10,424)				(10,424)
Stock repurchased	(8,778)					(8,778)
Stock issued under employee plans (in shares)		91
Stock issued under employee plans	1,698	$ (2)	1,700
Excess tax benefit on stock awards	1,044		1,044
Stock based compensation expense	2,477		2,477
Stock issued to directors (in shares)		10
Stock issued to directors	$ 350		350
Change in par value		$ (2,214)	2,214
Ending Balance (in shares) at Dec. 31, 2015	24,733	24,732
Ending Balance at Dec. 31, 2015	$ 245,225	$ 247	$ 76,746	$ 288,358	$ (34,585)	$ (85,541)