Recent Accounting Developments (Lease Costs) (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Accounting Changes and Error Corrections [Abstract]
Operating lease cost	$ 5,299	$ 17,357
Finance lease cost:
Amortization of right-of-use asset	15	15
Interest on lease liability	26	26
Short-term lease cost	134	446
Variable lease cost	724	2,213
Sublease income	(164)	(345)
Total lease cost	6,034	19,712
Cash paid for amounts included in the measurement of operating lease liabilities	6,458	18,156
Cash paid for amounts included in the measurement of finance lease liabilities	24	24
Right-of-use asset obtained in exchange for new operating lease liabilities	587	3,635
Right-of-use asset obtained in exchange for new finance lease liabilities	$ 3,498	$ 3,498
Weighted average remaining lease term - operating leases	13 months 21 days	13 months 21 days
Weighted average remaining lease term - finance leases	39 months 24 days	39 months 24 days
Weighted average discount rate - operating leases	4.10%	4.10%
Weighted average discount rate - finance leases	4.43%	4.43%