Fair Value Measurements (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Aug. 10, 2017
Fair Value Disclosures [Abstract]
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount		$ 0		$ 0
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	$ 0	0	$ 0	0
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	0	0	0	0
Business Combination, Contingent Consideration, Liability	60,300,000		60,300,000		$ 52,300,000
Gain (Loss) on Embedded Derivative, Net	$ 8,000,000	$ 0	$ 8,000,000	$ 0