Fair Values of Financial and Nonfinancial Instruments (Details 2) (Mortgage interest rate lock commitments ("IRLCs"), USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Mortgage interest rate lock commitments ("IRLCs")
Fair value assets reconciliation of changes
Fair value at the beginning of the period			$ 1,496,000	$ 2,055,000
Additions			14,098,000	14,415,000
Gains realized on the conversion of IRLCs to loans	(4,200,000)	(4,100,000)	(10,696,000)	(14,763,000)
Change in valuation of items held			350,000	1,018,000
Fair value at the end of the period	5,248,000	2,725,000	5,248,000	2,725,000
Increase (decrease) in fair value of the pipeline of IRLCs	2,000,000	(347,000)	3,800,000	670,000
Offsetting gains or (losses) from instruments used to hedge IRLCs	$ (4,300,000)	$ (1,700,000)	$ (6,500,000)	$ (6,600,000)