Leases (Schedule of Operating Lease Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Subsidiaries [Member]
Operating Leases, Rent Expense, Net [Abstract]
Operating lease expense net of sublease receipts	$ 34,093	$ 35,198	$ 31,786