Shareholders Equity (Schedule Of Changes In Non-Vested Restricted Shares) (Details) (USD $)	6 Months Ended
	Jun. 30, 2012
Shareholders' Equity
Non-vested shares at beginning of period, Number of Shares	732,412
Non-vested shares at beginning of period, Weighted Average Grant Price	$ 21.91
Shares granted, Number of Shares	281,429
Shares granted, Weighted Average Grant Price	$ 26.78
Shares vested, net of shares repurchased to cover tax withholding requirements,, Number of Shares	(183,019)
Shares vested, net of shares repurchased to cover tax withholding requirements, , Weighted Average Grant Price	$ 25.98
Shares forfeited, Number of Shares	(448)
Shares forfeited, Weighted Average Grant Price	$ 24.75
Non-vested shares at end of period, Number of Shares	830,374
Non-vested shares at end of period, Weighted Average Grant Price	$ 22.51