Leases (Lease Costs and Supplemental Cash Flow Information Related to Leases) (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
		Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Operating lease costs		$ 3,972	$ 7,933
Short-term lease costs (1)	[1]	938	1,818
Total lease costs		$ 4,910	9,751
Cash paid for operating leases included in the measurement of lease liabilities			7,847
ROU assets obtained in exchange for lease liabilities			$ 73,041

[1] Includes variable lease costs which are immaterial.