Summary of Significant Accounting Policies (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Carrying Value
Carrying value and estimated fair value of debt
Credit Agreement (carrying value including current maturities)	$ 127,500	$ 135,000
Convertible debt (par value)	150,000	150,000
Fair Value
Carrying value and estimated fair value of debt
Credit Agreement (carrying value including current maturities)	127,500	135,000
Convertible debt (par value)	$ 188,145	$ 199,800