Long-Term Debt (Interest Rate Swaps) (Details) - Interest Rate Swap [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Jun. 30, 2014
Derivative [Line Items]
Derivative, Notional Amount						$ 500,000
Derivative, Fixed Interest Rate						1.57%
Remaining Balance Of Interest Rate Swap Notional Amount						$ 250,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	$ (8,818)		$ (8,818)		$ (3,781)
Market value adjustments on interest rate swap, net of tax	2,043	$ (970)	3,110	$ (285)
Deferred Taxes Pertaining To Other Comprehensive Income Relating to Swaps	$ 1,300	$ (600)	$ 1,900	$ (200)
December 2018 [Member]
Derivative [Line Items]
Quarterly Amortization of Interest Rate Swap Notional Amount						$ 25,000