Acquisitions (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Reduction in contingent consideration	$ 3,789
Challenger And Hybrid [Member]
Business Acquisition [Line Items]
Acquisition purchase price	22,785
Acquisition purchase price based on future performance	6,000
Challenger And Hybrid [Member] | Other Long-Term Liabilities [Member]
Business Acquisition [Line Items]
Acquisition purchase price based on future performance	2,100
Challenger And Hybrid [Member] | Accrued Expenses And Other Current Liabilities [Member]
Business Acquisition [Line Items]
Acquisition purchase price based on future performance	$ 100