Leases (Lease Cost and other Lease Information) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Lease, Cost [Abstract]
Operating lease cost	$ 3,136	$ 9,495
Variable lease cost	998	2,592
Short-term lease cost	153	370
Interest on lease liabilities	187	561
Amortization of right-of-use assets	18	54
Sublease income	(2,122)	(6,383)
Net lease cost	2,370	6,689
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	3,259	9,584
Operating cash flows from finance leases	187	561
Financing cash flows from finance leases	20	58
Right-of-use assets obtained in exchange for new operating lease liabilities	392	2,117
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 0	$ 0