Consolidated Statement of Shareholders' Equity - 9 months ended Sep. 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	41,427			41,427
Foreign currency translation adjustment	10,638				10,638
Adjustment to retirement benefit liability, net of taxes of ($2)	59				59
Adjustment to post employment health care benefit liability, net of taxes of $70	114				114
Stock compensation expense	4,666		4,666
Excess tax benefit from stock compensation	941		941
Stock options exercised, shares		151
Stock options exercised	2,892	$ 2	2,890
Issuance of restricted stock, shares		0
Issuance of restricted stock	0	$ 0	0
Net settlement of restricted stock units, shares		110				37
Net settlement of restricted stock units	(1,178)	$ 1	(1)			$ (1,178)
Balance, shares at Sep. 30, 2016		32,040				521
Balance, value at Sep. 30, 2016	$ 469,645	$ 320	$ 261,954	$ 219,500	$ (4,605)	$ (7,524)