The Company and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) Share data in Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 Categories	Mar. 31, 2012
Organization and Summary of Significant Accounting Policies Disclosure [Line Items]
Number of business channels	2
Number of revenue and cost categories	2
Unvested service-based restricted stock awards included in the calculation of earnings per share	0.8	0.9
Non Interest Bearing Deposits
Organization and Summary of Significant Accounting Policies Disclosure [Line Items]
Cash subject to FDIC insurance	9,700,000
Cash not subject to FDIC insurance	54,000,000
Non Interest Bearing Deposits | Maximum
Organization and Summary of Significant Accounting Policies Disclosure [Line Items]
Cash subject to FDIC insurance	250,000