Stock-Based Compensation (Summary Of Stock-Based Awards) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Restricted Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested shares outstanding, Shares, Beginning balance	340
Vested, Shares	(86)
Forfeited, Shares	(6)
Non-vested shares outstanding, Shares, Ending balance	248
Non-vested shares outstanding, Weighted-Average Grant Date Fair Value, Beginning balance	$ 16.81
Vested, Weighted-Average Grant Date Fair Value	$ 16.84
Forfeited, Weighted-Average Grant Date Fair Value	$ 16.77
Non-vested shares outstanding, Weighted-Average Grant Date Fair Value, Ending balance	$ 16.80
Restricted Stock Units And Phantom Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested shares outstanding, Shares, Beginning balance	103
Granted, Shares	234
Vested, Shares	(31)
Forfeited, Shares	(2)
Non-vested shares outstanding, Shares, Ending balance	304
Non-vested shares outstanding, Weighted-Average Grant Date Fair Value, Beginning balance	$ 16.70
Granted, Weighted-Average Grant Date Fair Value	$ 17.37
Vested, Weighted-Average Grant Date Fair Value	$ 16.38
Forfeited, Weighted-Average Grant Date Fair Value	$ 17.14
Non-vested shares outstanding, Weighted-Average Grant Date Fair Value, Ending balance	$ 17.25
Performance Based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested shares outstanding, Shares, Beginning balance	164
Granted, Shares	76	[1]
Non-vested shares outstanding, Shares, Ending balance	240	[1]
Non-vested shares outstanding, Weighted-Average Grant Date Fair Value, Beginning balance	$ 16.39
Granted, Weighted-Average Grant Date Fair Value	$ 17.37	[1]
Non-vested shares outstanding, Weighted-Average Grant Date Fair Value, Ending balance	$ 16.70	[1]

[1] Represents target number of shares that can vest based on the achievement of certain performance criteria.