Fair Values of Financial and Nonfinancial Instruments (Details 2) (Mortgage interest rate lock commitments ("IRLCs"), USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Mortgage interest rate lock commitments ("IRLCs")
Fair value assets reconciliation of changes
Fair value at the beginning of the period			$ 3,359,000	$ 1,496,000
Additions			12,092,000	8,448,000
Gain realized on conversion to loans	(5,900,000)	(3,800,000)	(9,812,000)	(6,453,000)
Change in valuation of items held			(215,000)	(224,000)
Fair value at the end of the period	5,424,000	3,267,000	5,424,000	3,267,000
Increase (decrease) in fair value of the pipeline of IRLCs	1,500,000	543,000	2,100,000	1,800,000
Offsetting gains (losses) from instruments used to hedge IRLCs	$ (3,400,000)	$ (2,000,000)	$ (3,900,000)	$ (2,200,000)