Fair Value Measurements (Level 3 Valuation Techniques) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Fair Value Measurements, Recurring and nonrecurring, Valuation Techniques [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	$ 11,200	$ 6,073	$ 13,624	$ (6,412)	$ (1,168)	$ 0
Income Approach Valuation Technique
Fair Value Measurements, Recurring and nonrecurring, Valuation Techniques [Line Items]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs	$ 11,200
Income Approach Valuation Technique | Minimum
Fair Value Measurements, Recurring and nonrecurring, Valuation Techniques [Line Items]
Volatility Range	22.60%
Income Approach Valuation Technique | Maximum
Fair Value Measurements, Recurring and nonrecurring, Valuation Techniques [Line Items]
Volatility Range	41.30%