Property And Equipment, Net (Summary Of Depreciation And Amortization, Capitalized Computer Software For Internal Use And Unpaid Property Equipment Reflected In Account Payable And Accrued Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 63,537	$ 57,029	$ 48,783
Unpaid property and equipment, reflected in accounts payable and accrued liabilities	10,601	8,534	6,513
Software Developed For Internal Use [Member]
Property, Plant and Equipment [Line Items]
Capitalized computer software developed for internal use	$ 15,590	$ 19,081	$ 11,871