Derivatives Financial Instruments (Rollforward Of Amounts In Accumulated Other Comprehensive Income Related To Interest Rate Swaps Designated As Cash Flow Hedges) (Details) (USD $) In Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2011	Mar. 31, 2011	Jun. 30, 2010	Mar. 31, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Dec. 31, 2009
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Unrealized loss at beginning of period	$ (10,120)	$ (11,202)	$ (15,969)	$ (15,754)	$ (10,120)	$ (15,969)	$ (13,323)	$ (15,487)
Amount reclassified from accumulated other comprehensive income to interest expense on junior subordinated debentures	2,197		2,199		4,369	4,392
Amount of loss recognized in other comprehensive income	(1,115)		(2,414)		(1,166)	(4,874)
Unrealized loss at end of period	$ (10,120)	$ (11,202)	$ (15,969)	$ (15,754)	$ (10,120)	$ (15,969)	$ (13,323)	$ (15,487)