Fair Value Measurements (Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation) (Details) - Contingent Consideration Liability [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Contingent consideration for acquisitions
Balance at beginning of period	$ (20,981)	$ (3,000)
Additions for acquisitions	0	(13,814)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Payments	21,594	0
Fair value adjustment	(613)	(4,167)
Balance at end of period	$ 0	$ (20,981)