Recent Accounting Developments (Lease Costs) (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Accounting Changes and Error Corrections [Abstract]
Operating lease cost	$ 5,963	$ 12,058
Short-term lease cost	131	312
Variable lease cost	713	1,489
Sublease income	(98)	(181)
Total lease cost	6,709	13,678
Cash paid for amounts included in the measurement of operating lease liabilities	$ 5,935	$ 11,698
Weighted average remaining lease term - operating leases	13 months 18 days	13 months 18 days
Weighted average discount rate - operating leases	4.02%	4.02%