Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Components of Long-term Debt
Total long-term debt	$ 379,155	$ 386,755
8.625% Senior Notes [Member]
Components of Long-term Debt
Total long-term debt	300,000	300,000
Revolving Credit Facility [Member]
Components of Long-term Debt
Total long-term debt	$ 79,155	$ 86,755