Consolidated Statement of Shareholders' Equity - 6 months ended Jun. 30, 2016 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Balance, shares at Dec. 31, 2015		31,779				484
Balance, value at Dec. 31, 2015	$ 410,086	$ 317	$ 253,458	$ 178,073	$ (15,416)	$ (6,346)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	23,482			23,482
Foreign currency translation adjustment	10,831				10,831
Adjustment to retirement benefit liability, net of taxes of $1	(2)				(2)
Adjustment to post employment health care benefit liability, net of taxes of $47	76				76
Reclassification of loss on cash flow hedges, net of tax of $82	0
Stock compensation expense	3,218		3,218
Excess tax benefit from stock compensation	292		292
Stock options exercised, shares		104
Stock options exercised	2,058		2,057
Issuance of restricted stock, shares		0
Issuance of restricted stock	0	$ 0	0
Net settlement of restricted stock units, shares		47				18
Net settlement of restricted stock units	(462)	$ 1	(1)			$ (462)
Balance, shares at Jun. 30, 2016		31,930				502
Balance, value at Jun. 30, 2016	$ 449,579	$ 319	$ 259,024	$ 201,555	$ (4,511)	$ (6,808)