Long-Term Debt (Interest Rate Swaps) (Details) - Interest Rate Swap [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Derivative [Line Items]
Derivative, Notional Amount	$ 500,000		$ 500,000
Derivative, Fixed Interest Rate	1.57%		1.57%
Remaining Balance Of Interest Rate Swap Notional Amount	$ 250,000		$ 250,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative [Line Items]
Derivative Financial Instruments, Liabilities, Fair Value Disclosure	(5,510)		(5,510)		$ (3,781)
Market value adjustments on interest rate swap, net of tax	(1,113)	$ 612	1,067	$ 684
Deferred Taxes Pertaining To Other Comprehensive Income Relating to Swaps	(700)	$ 400	700	$ 400
December 2018 [Member]
Derivative [Line Items]
Quarterly Amortization of Interest Rate Swap Notional Amount	$ 25,000		$ 25,000