Leases (Schedule of Lease Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Lease, Cost [Abstract]
Operating lease costs	$ 8,116		$ 16,242
Short-term lease costs	209		476
Variable lease costs	(5)		(3)
Sublease income	(615)		(1,402)
Net lease costs	$ 7,705		$ 15,313
Rent expense		$ 9,400		$ 19,000
Rent income		$ 648		$ 1,300