Fair Values of Assets and Liabilities - Valuation Assumption Ranges for Derivative Commitments (Detail)	Jun. 30, 2013 BasisPoint
Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Expected loan close rate	42.00%
Inherent MSR value (basis points per loan)	44
Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Expected loan close rate	100.00%
Inherent MSR value (basis points per loan)	221
Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Expected loan close rate	83.00%
Inherent MSR value (basis points per loan)	120