Fair Value (Narrative) (Details) (USD $)	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2011	Sep. 30, 2011	Dec. 31, 2010	Jun. 30, 2011
Fair Value [Abstract]
Book value of impaired loans	$ 192,464,000	$ 192,464,000	$ 250,933,000
Partial charge-offs on impaired loans		95,900,000	53,600,000
Valuation allowance of impaired loans	33,275,000	33,275,000	43,459,000
Book value of impaired loans carried at fair value	123,200,000	123,200,000
Remaining amount of impaired loans carried at cost		69,200,000	96,200,000
MSR recorded at lower of cost or fair value	10,069,000	10,069,000	10,488,000	10,259,000
Mortgage servicing rights	4,963,000	4,963,000	3,813,000
Valuation allowance of MSR	680,000	680,000	748,000	680,000
MSRs recorded at cost	5,100,000	5,100,000
Devaluation adjustments of OREO	1,700,000	11,300,000
Impaired loans carried at fair value, Fair value	89,857,000	89,857,000	111,257,000
Estimated fair value of OREO, less estimated selling costs	$ 46,911,000	$ 46,911,000	$ 44,325,000