Fair Value of Financial Instruments (Details 2) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2010
Purchases, issuances, sales and settlements
Carrying amount of loans intended to be sold in near term	$ 121,200,000
Loans held-for-sale at fair value
Movement of investment in available-for-sale debt securities
Balance at beginning of the period	144,163,000
Purchases, issuances, sales and settlements
Purchases		144,163,000
Originations	270,066,000
Transfer in	(7,000,000)
Sales	(294,149,000)
Settlements	(131,000)
Purchases, issuances, sales and settlements value	(31,214,000)
Unrealized gain (loss) on assets	(1,725,000)
Realized gain (loss) on assets	10,337,000
Other	(332,000)
Net gain (loss) on assets	8,280,000
Balance at end of the period	121,229,000	144,163,000
Mortgage-backed securities
Purchases, issuances, sales and settlements
Purchases	94,544,000
Transfer in	282,763,000
Settlements	(17,474,000)
Purchases, issuances, sales and settlements value	359,833,000
Unrealized gain (loss) on assets	(11,952,000)
Accretion of discount	5,111,000
OTTI	(892,000)
Net gain (loss) on assets	(7,733,000)
Balance at end of the period	352,100,000
Fair value measurements on recurring basis
Purchases, issuances, sales and settlements
Purchases	94,544,000
Originations	270,066,000
Transfer in	275,763,000
Sales	(294,149,000)
Settlements	(17,605,000)
Purchases, issuances, sales and settlements value	328,619,000
Unrealized gain (loss) on assets	(13,677,000)
Realized gain (loss) on assets	10,337,000
Accretion of discount	5,111,000
OTTI	(892,000)
Other	(332,000)
Net gain (loss) on assets	547,000
Balance at end of the period	$ 473,329,000