CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Comprehensive Income
Balance at Dec. 31, 2008	$ 44,619	$ 471		$ 73,595	$ (29,447)
Increase (Decrease) in Stockholders' Equity
Net income	27,353			27,353		27,353
Foreign currency translation adjustment	18,709				18,709	18,709
Change in the fair value of interest rate swap contracts (net of income taxeffect of $1,574, $3,471 and $20 for year ended 2011, 2010 and 2009 respectively)	30				30	30
Pension and other post-retirement liabilities (net of income tax effect of $7,239, $2,056 and $305 for year ended 2011, 2010 and 2009 respectively)	481				481	481
Total comprehensive income	46,573					46,573
Shares issued for consideration:
Shares issued under stock incentive plan (762,004, 50,446 and 40,818 shares for year ended 2011, 2010 and 2009 respectively)	0
Shares issued under employee stock purchase plan (2,567, 3,251 and 6,716 shares for year ended 2011, 2010 and 2009 respectively)	52		52
Shares issued to Board of Directors in lieu of cash (2,739, 3,603 and 7,314 shares for year ended 2011, 2010 and 2009 respectively)	60		60
Stock-based compensation, net of forfeitures (30,000, 12,000 and 65,735 shares for year ended 2011, 2010 and 2009 respectively)	8,210		8,210
Cash dividend ($.36, $.12 and $.18 per share for year ended 2011, 2010 and 2009 respectively)	(8,365)			(8,365)
Purchase of common stock (768,780, 869,065 and 180,833 shares for year ended 2011, 2010 and 2009 respectively)	(1,587)	(1)	(1,586)
Balance at Dec. 31, 2009	89,562	470	6,736	92,583	(10,227)
Increase (Decrease) in Stockholders' Equity
Net income	28,024			28,024		28,024
Foreign currency translation adjustment	(315)				(315)	(315)
Change in the fair value of interest rate swap contracts (net of income taxeffect of $1,574, $3,471 and $20 for year ended 2011, 2010 and 2009 respectively)	5,122				5,122	5,122
Pension and other post-retirement liabilities (net of income tax effect of $7,239, $2,056 and $305 for year ended 2011, 2010 and 2009 respectively)	2,259				2,259	2,259
Total comprehensive income	35,090					35,090
Shares issued for consideration:
Exercise of stock options, including tax benefit of $1,668 (878,658 shares) and $479 (790,596 shares) for year ended 2011 and 2010 respectively)	10,122	8	10,114
Shares issued under stock incentive plan (762,004, 50,446 and 40,818 shares for year ended 2011, 2010 and 2009 respectively)	0
Shares issued under employee stock purchase plan (2,567, 3,251 and 6,716 shares for year ended 2011, 2010 and 2009 respectively)	44		44
Shares issued to Board of Directors in lieu of cash (2,739, 3,603 and 7,314 shares for year ended 2011, 2010 and 2009 respectively)	50		50
Stock-based compensation, net of forfeitures (30,000, 12,000 and 65,735 shares for year ended 2011, 2010 and 2009 respectively)	9,208		9,208
Cash dividend ($.36, $.12 and $.18 per share for year ended 2011, 2010 and 2009 respectively)	(5,617)			(5,617)
Purchase of common stock (768,780, 869,065 and 180,833 shares for year ended 2011, 2010 and 2009 respectively)	(12,073)	(8)	(12,065)
Balance at Dec. 31, 2010	126,386	470	14,087	114,990	(3,161)
Increase (Decrease) in Stockholders' Equity
Net income	58,011			58,011		58,011
Foreign currency translation adjustment	(2,525)				(2,525)	(2,525)
Change in the fair value of interest rate swap contracts (net of income taxeffect of $1,574, $3,471 and $20 for year ended 2011, 2010 and 2009 respectively)	2,622				2,622	2,622
Pension and other post-retirement liabilities (net of income tax effect of $7,239, $2,056 and $305 for year ended 2011, 2010 and 2009 respectively)	(11,439)				(11,439)	(11,439)
Total comprehensive income	46,669					46,669
Shares issued for consideration:
Exercise of stock options, including tax benefit of $1,668 (878,658 shares) and $479 (790,596 shares) for year ended 2011 and 2010 respectively)	14,819	15	14,804
Shares issued under stock incentive plan (762,004, 50,446 and 40,818 shares for year ended 2011, 2010 and 2009 respectively)	0
Shares issued under employee stock purchase plan (2,567, 3,251 and 6,716 shares for year ended 2011, 2010 and 2009 respectively)	37		37
Shares issued to Board of Directors in lieu of cash (2,739, 3,603 and 7,314 shares for year ended 2011, 2010 and 2009 respectively)	50		50
Stock-based compensation, net of forfeitures (30,000, 12,000 and 65,735 shares for year ended 2011, 2010 and 2009 respectively)	9,671		9,671
Cash dividend ($.36, $.12 and $.18 per share for year ended 2011, 2010 and 2009 respectively)	(17,183)			(17,183)
Purchase of common stock (768,780, 869,065 and 180,833 shares for year ended 2011, 2010 and 2009 respectively)	(15,026)	(8)	(15,018)
Balance at Dec. 31, 2011	$ 165,423	$ 477	$ 23,631	$ 155,818	$ (14,503)