Interim Statements of Stockholders' Equity Statement (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income
Balance at Dec. 31, 2013	$ 350,465	$ 1,211	$ 91,439	$ (426)	$ 255,203	$ 3,038
Balance (shares) at Dec. 31, 2013	12,070,509	12,071,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	29,800	0	0	0	29,800	0
Translation adjustment	(8,549)	0	0	0	0	(8,549)
Net actuarial gain arising during period, net of taxes	262	0	0	0	0	262
Stock-based compensation	1,801	0	1,801	0	0	0
Exercise of stock options	429	3	426	0	0	0
Exercise of stock options (shares)	23,231	23,000
Repurchased shares (note 4)	(34,204)	0	0	(34,204)	0	0
Retirement of shares (shares)	(849,690)	(850,000)
Retirement of shares (note 4)	0	(85)	(569)	34,204	(33,550)	0
Dividends paid ($.21 per share)	(2,540)	0	0	0	(2,540)	0
Balance at Sep. 30, 2014	$ 337,464	$ 1,129	$ 93,097	$ (426)	$ 248,913	$ (5,249)
Balance (shares) at Sep. 30, 2014	11,244,050	11,244,000