Treasury And Common Stock - Schedule Of Treasury Stock (Details) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012
Class of Stock [Line Items]
Treasury Stock, Beginning Balance, Amount	$ (441,774)		$ (426,717)
Treasury stock purchases	(10,266)	[1]	(8,929)	[1]
Treasury Stock, Ending Balance, Amount	(452,040)
Treasury Stock, Shares, Beginning Balance	9,944,239		9,204,340
Treasury Stock, Shares, Ending Balance	10,557,342
Excluding Long-Term Incentive Plan [Member]
Class of Stock [Line Items]
Treasury stock purchases	(9,961)		(7,306)
Treasury stock purchased in connection with long-term incentive plan, Shares	594,582		283,300
Long-Term Incentive Plan [Member]
Class of Stock [Line Items]
Treasury stock purchases	(305)		(1,623)
Treasury Stock, Ending Balance, Amount			$ 435,646
Treasury stock purchased in connection with long-term incentive plan, Shares	18,521		45,263
Treasury Stock, Shares, Ending Balance			9,532,903

[1] This includes shares withheld in order to satisfy employee withholding taxes upon the distribution of vested restricted stock units.