Fair Value (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012
Fair Value
Fair Value Instruments Transfers Between Levels	$ 0	$ 0
Carrying Amount | Level 3 | Term Loan
Fair Value
Long-term debt and interest payable	170,000,000	187,670,000
Carrying Amount | Level 2 | Notes
Fair Value
Long-term debt and interest payable	306,563,000	314,438,000
Fair Value | Level 3
Fair Value
Long-term debt and interest payable	170,000,000	188,000,000
Fair Value | Level 3 | Term Loan
Fair Value
Long-term debt and interest payable	170,000,000	188,046,000
Fair Value | Level 2 | Notes
Fair Value
Long-term debt and interest payable	$ 344,852,000	$ 352,368,000