Revolving Credit Facility and Long-Term Debt - Principal Balances under Long-term Debt (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Line of Credit Facility [Line Items]
Total long-term debt	$ 237,566	$ 30,737
Less current portion	10,000	0
Long-term portion	227,566	30,737
Term Loan [Member]
Line of Credit Facility [Line Items]
Total long-term debt	100,000	0
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Total long-term debt	$ 137,566	$ 30,737