Long-Term Debt (Details) (USD $)	12 Months Ended		0 Months Ended	12 Months Ended				0 Months Ended	12 Months Ended						0 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Apr. 13, 2011 Interest rate swap agreement	Dec. 31, 2013 Interest rate swap agreement	Dec. 31, 2012 Interest rate swap agreement	Dec. 31, 2011 Interest rate swap agreement	Dec. 31, 2012 Senior Notes due March 2016	Mar. 31, 2011 Revolving credit line	Dec. 31, 2013 Revolving credit line	Dec. 31, 2012 Revolving credit line	Dec. 31, 2011 Revolving credit line	Dec. 31, 2013 Term loan	Dec. 31, 2012 Term loan	Mar. 31, 2011 Term loan	Jul. 30, 2013 Term Loan Facility	Dec. 31, 2013 Term Loan Facility	Jul. 30, 2013 Senior Notes due June 2017
Long-term debt
Long-term debt							$ 57,012,000					$ 0	$ 57,000,000			$ 172,481,000
Less: current portion	(1,750,000)	(4,608,000)
Long-term debt less current portion	170,731,000	52,404,000
Amount of term loan														66,000,000	175,000,000
Uncommitted accordion option base amount															20,000,000
Uncommitted accordion option multiplier of 1st lien net leverage															4.0
Reference rate basis															LIBOR
Interest rate margin (as a percent)															5.00%
Interest rate floor (as a percent)															1.25%
Effective interest rate (as a percent)															6.25%
OID (as a percent)															1.00%
OID																1,700,000
Accumulated amortization of original issue discount																100,000
Net debt issue costs																3,300,000
Accumulated amortization	200,000	1,500,000														200,000
Loss on early extinguishment of debt	1,649,000															1,600,000
Maximum period after each fiscal year for prepayment of debt																90 days
Prepayment of debt as a percentage of excess cash flow																50.00%
First prepayment of debt as a percentage of excess cash flow, if lower leverage ratio is maintained																25.00%
Second prepayment of debt as a percentage of excess cash flow, if lower leverage ratio is maintained																0.00%
Borrowing capacity								10,000,000
Annual commitment fee (as a percent)								0.75%
Commitment fee									37,192	75,000	60,000
Maturity term			2 years
Initial notional amount			33,000,000
Variable rate basis for interest receivable			Three months LIBOR
Fixed rate of interest (as a percent)			1.143%
Fair value				0	100,000
Additional financing income (expense) related to the change in the fair value of derivatives				100,000	100,000	(200,000)
Amount outstanding																	30,100,000
Maturities of long-term debt
2014	1,750,000
2015	1,750,000
2016	1,750,000
2017	1,750,000
2018 and thereafter	167,125,000
Total maturities	$ 174,125,000