Income Taxes (Schedule of Provisions of Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current Income Tax Expense (Benefit), Continuing Operations
Federal	$ 62,274	$ 61,073	$ 31,132
State and local	10,720	10,560	7,670
Foreign	158	466	160
Total current provision	73,152	72,099	38,962
Deferred Income Tax Expense (Benefit), Continuing Operations
Federal	7,614	(2,506)	466
State and local	(806)	(110)	596
Foreign	0	18	0
Total deferred provision	6,808	(2,598)	1,062
Provision for income taxes	$ 79,960	$ 69,501	$ 40,024