Business Combinations (Details) (USD $)			3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Nevada Commerce Bank Y	Jun. 30, 2011 Nevada Commerce Bank	Apr. 08, 2011 Nevada Commerce Bank	Feb. 11, 2011 Branch office in San Jose
Business acquisitions
Carrying value of assets acquired					$ 138,900,000
Carrying value of liabilities assumed					121,900,000
Acquired goodwill						300,000
Core deposit intangible						100,000
Covered loans					56,400,000
Covered other real estate owned					7,500,000
Deposits					118,400,000	8,400,000
Cash from the FDIC					2,700,000
FDIC reimbursement (as a percent)			80.00%
Term of loss-sharing agreements for single family residential loans (in years)			10
Term of loss-sharing agreements for other loans (in years)			8
FDIC indemnification asset	185,392,000	204,259,000			33,800,000
Gain on acquisition				$ 8,200,000