Financial Instruments Measured at Fair Value - Unobservable Inputs Reconciliation (Details) (Fair Value, Inputs, Level 3 [Member], Fair Value, Measurements, Recurring [Member], Contingent Consideration [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member] | Contingent Consideration [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance as of December 31, 2011	$ 0
Fair value of initial contingent consideration	(10,390)
Change in fair value of contingent consideration included in earnings	(766)
Balance as of June 30, 2012	$ (11,156)