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, 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 tax effect of $1,574 and $3,471 for the year ended 2011 and 2010 respectively)	5,122				5,122	5,122
Pension and other post-retirement liabilities (net of income tax effect of $7,807, $7,239 and $2,056 for the year ended 2012, 2011 and 2010 respectively)	2,259				2,259	2,259
Total comprehensive income	35,090					35,090
Shares issued for consideration:
Exercise of stock options (93,839, 878,658 and 790,596 shares for the year ended 2012, 2011 and 2010 respectively)	9,643	8	9,635
Income tax effect from the exercise of stock options and vesting of restricted stock	479		479
Shares issued under employee stock purchase plan (2,567 and 3,251 shares for the year ended 2011 and 2010 respectively)	44		44
Shares issued to Board of Directors in lieu of cash (3,391, 2,739 and 3,603 shares for the year ended 2012, 2011 and 2010 respectively)	50		50
Stock-based compensation	9,208		9,208
Cash dividend ($.44, $.36 and $.12 per share for the year ended 2012, 2011 and 2010 respectively)	(5,617)			(5,617)
Purchase of common stock (310,252, 768,780 and 869,065 shares for the year ended 2012, 2011 and 2010 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 tax effect of $1,574 and $3,471 for the year ended 2011 and 2010 respectively)	2,622				2,622	2,622
Pension and other post-retirement liabilities (net of income tax effect of $7,807, $7,239 and $2,056 for the year ended 2012, 2011 and 2010 respectively)	(11,439)				(11,439)	(11,439)
Total comprehensive income	46,669					46,669
Shares issued for consideration:
Exercise of stock options (93,839, 878,658 and 790,596 shares for the year ended 2012, 2011 and 2010 respectively)	13,151	15	13,136
Income tax effect from the exercise of stock options and vesting of restricted stock	1,668		1,668
Shares issued under employee stock purchase plan (2,567 and 3,251 shares for the year ended 2011 and 2010 respectively)	37		37
Shares issued to Board of Directors in lieu of cash (3,391, 2,739 and 3,603 shares for the year ended 2012, 2011 and 2010 respectively)	50		50
Stock-based compensation	9,671		9,671
Cash dividend ($.44, $.36 and $.12 per share for the year ended 2012, 2011 and 2010 respectively)	(17,183)			(17,183)
Purchase of common stock (310,252, 768,780 and 869,065 shares for the year ended 2012, 2011 and 2010 respectively)	(15,026)	(8)	(15,018)
Balance at Dec. 31, 2011	165,423	477	23,631	155,818	(14,503)
Increase (Decrease) in Stockholders' Equity
Net income	50,001			50,001		50,001
Foreign currency translation adjustment	1,981				1,981	1,981
Pension and other post-retirement liabilities (net of income tax effect of $7,807, $7,239 and $2,056 for the year ended 2012, 2011 and 2010 respectively)	(12,358)				(12,358)	(12,358)
Total comprehensive income	39,624					39,624
Shares issued for consideration:
Exercise of stock options (93,839, 878,658 and 790,596 shares for the year ended 2012, 2011 and 2010 respectively)	1,041	2	1,039
Income tax effect from the exercise of stock options and vesting of restricted stock	(2,652)		(2,652)
Shares issued under stock incentive plan (315,030, 762,004 and 50,446 shares for the year ended 2012, 2011 and 2010 respectively)	3	3
Shares issued to Board of Directors in lieu of cash (3,391, 2,739 and 3,603 shares for the year ended 2012, 2011 and 2010 respectively)	50		50
Stock-based compensation	10,356		10,356
Cash dividend ($.44, $.36 and $.12 per share for the year ended 2012, 2011 and 2010 respectively)	(21,069)			(21,069)
Purchase of common stock (310,252, 768,780 and 869,065 shares for the year ended 2012, 2011 and 2010 respectively)	(4,676)	(3)	(4,673)
Balance at Dec. 31, 2012	$ 188,100	$ 479	$ 27,751	$ 184,750	$ (24,880)