Convertible Notes, Long-Term Debt and Credit Facility - Credit Facility (Details) (USD $)	6 Months Ended
	Jun. 30, 2013
Line of Credit Facility [Line Items]
Credit facility, financial covenant, EBITDA to debt ratio, upper range	110.00%
Credit facility, financial covenant, EBITDA to debt ratio, lower range	100.00%
Credit facility, financial covenant, funded debt to adjusted EBITDA ratio	4.0
Credit facility, covenant terms	The Credit Facility is secured by substantially all of the Company’s domestic personal property, including accounts receivable, inventory, equipment and other intangible assets. The Credit Facility contains customary representations, warranties, and both affirmative and negative covenants, including a financial covenant to maintain a consolidated earnings before interest, taxes, depreciation and amortization (“EBITDA”) to debt ratio of 1.10 to 1.00, a financial covenant to maintain a ratio of funded debt to adjusted EBITDA of not greater than 4.0 to 1.0, and an annual limit on capital expenditures of approximately $36 million. The Credit Facility restricts the payment of cash dividends on common stock. In the event of default, PNC Bank may accelerate the maturity date of any outstanding amounts borrowed under the Credit Facility.
Credit facility, interest rate description	The interest rate on advances under the revolving credit facility varies based on the level of borrowing. Rates range (a) between PNC Bank's base lending rate plus 0.5% to 1.0% or (b) between the London Interbank Offered Rate (LIBOR) plus 1.5% to 2.0%. PNC Bank's base lending rate was 3.25% at June 30, 2013. The Company is required to pay a monthly facility fee of 0.25% on any unused amount under the commitment based on daily averages. At June 30, 2013, $37.6 million was outstanding under the revolving credit facility at an interest rate of 3.75% and $25.0 million borrowed as LIBOR loans at an interest rate of 1.70%.
Line of Credit [Member]
Line of Credit Facility [Line Items]
Annual limit on capital expenditures	$ 36,000,000
Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	75,000,000
Credit facility, commitment fee percentage	0.25%
Credit facility, amount outstanding	37,600,000
Credit facility, availability	62,000,000
Letter of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	10,000,000
Term loan [Member]
Line of Credit Facility [Line Items]
Debt, face amount	50,000,000
Amount borrowed	49,400,000
Monthly principal payments	600,000
PNC Bank Base Rate [Member] | Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, amount outstanding	12,600,000
Credit facility, interest rate at period end	3.75%
PNC Bank Base Rate [Member] | Term loan [Member]
Line of Credit Facility [Line Items]
Amount borrowed	1,400,000
Debt, interest rate at period end	4.50%
London Interbank Lending Rate (LIBOR) [Member] | Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Base lending rate	3.25%
Credit facility, amount outstanding	25,000,000
Credit facility, interest rate at period end	1.70%
London Interbank Lending Rate (LIBOR) [Member] | Term loan [Member]
Line of Credit Facility [Line Items]
Amount borrowed	$ 48,000,000
Debt, interest rate at period end	2.45%
Minimum [Member] | PNC Bank Base Rate [Member] | Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, variable percentage rate spread	0.50%
Minimum [Member] | PNC Bank Base Rate [Member] | Term loan [Member]
Line of Credit Facility [Line Items]
Credit facility, variable percentage rate spread	1.25%
Minimum [Member] | London Interbank Lending Rate (LIBOR) [Member] | Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, variable percentage rate spread	1.50%
Minimum [Member] | London Interbank Lending Rate (LIBOR) [Member] | Term loan [Member]
Line of Credit Facility [Line Items]
Credit facility, variable percentage rate spread	2.25%
Maximum [Member] | PNC Bank Base Rate [Member] | Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, variable percentage rate spread	1.00%
Maximum [Member] | PNC Bank Base Rate [Member] | Term loan [Member]
Line of Credit Facility [Line Items]
Credit facility, variable percentage rate spread	1.75%
Maximum [Member] | London Interbank Lending Rate (LIBOR) [Member] | Line of Credit [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, variable percentage rate spread	2.00%
Maximum [Member] | London Interbank Lending Rate (LIBOR) [Member] | Term loan [Member]
Line of Credit Facility [Line Items]
Credit facility, variable percentage rate spread	2.75%