Commitments and Contingencies (Lease Costs, Cash Flows and Balance Sheet Supplemental Information) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2019
Leases [Abstract]
Operating lease cost	$ 6,461
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	6,515
Right-of-use assets obtained in exchange for new lease obligations:
Operating leases	66
Supplemental balance sheet information related to operating leases was as follows:
Operating lease right-of-use assets	24,876	$ 24,876
Operating lease liabilities	$ 24,876	$ 24,876
Weighted Average Remaining Lease Term
Operating leases	7 years 5 months 19 days
Weighted Average Discount Rate
Operating leases	3.20%