Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Senior Secured Debt	$ 383,588	$ 426,588
Debt, Weighted Average Interest Rate	4.60%
Term Loan Facility | $100 million term A loan facility, due May 2017
Debt Instrument [Line Items]
Senior Secured Debt	90,000	92,500
Debt Instrument, Interest Rate at Period End	3.20%
Term Loan Facility | $365 million term B loan facility, due May 2019
Debt Instrument [Line Items]
Senior Secured Debt	293,588	334,088
Debt Instrument, Interest Rate at Period End	5.00%
Revolving Credit Facility | $75 million revolving credit facility, due May 2017
Debt Instrument [Line Items]
Senior Secured Debt	$ 0	$ 0