Mortgage Banking (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Jun. 30, 2012	Oct. 31, 2013 Subsequent Event [Member]
Mortgage Banking [Abstract]
Gain on fair value hedge ineffectiveness, net	$ 1,300,000		$ 2,700,000
Loss on fair value hedge ineffectiveness, net		(1,800,000)		(2,700,000)
Period of put back response			60 days
Mortgage servicing rights [Abstract]
Balance at beginning of period			47,341,000	43,274,000
Origination of servicing assets			15,551,000	17,074,000
Change in fair value [Abstract]
Due to market changes			7,881,000	(8,960,000)
Due to runoff			(7,623,000)	(7,177,000)
Balance at end of period	63,150,000	44,211,000	63,150,000	44,211,000
Mortgage loan servicing representation and warranty expenses			1,000,000	7,200,000
Reserve for mortgage loan servicing put back expenses	5,000,000		5,000,000		7,800,000
Additional accrual for mortgage loan servicing representation and warranty expenses						4,000,000
Servicing Assets at Fair Value [Line Items]
Payments to FNMA for repurchase obligations							$ 4,400,000