Accrued Expenses (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Accrued Expenses
Accrued payroll and payroll related deductions and taxes	$ 17,451	$ 17,812
Accrued compensation arrangements	15,833	11,409
Accrued interest	11,882	12,196
Accrued other	5,717	4,984
Total accrued expenses	$ 50,883	$ 46,401