Long-term Debt - Principal Balances under Long-term Debt (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Line of Credit Facility [Line Items]
Total long-term debt	$ 240,484	$ 248,854
Less current portion	10,000	10,000
Long-term portion	230,484	238,854
Term Loan
Line of Credit Facility [Line Items]
Total long-term debt	85,000	92,500
Revolving Credit Facility
Line of Credit Facility [Line Items]
Total long-term debt	$ 155,484	$ 156,354