Fair Values of Assets and Liabilities - Valuation Assumption Ranges for MSRs (Detail)	Mar. 31, 2014	Dec. 31, 2013
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Expected prepayment	11.40%	11.20%
Discount rate	10.20%	10.20%
Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Expected prepayment	10.00%
Discount rate	10.00%
Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Expected prepayment	20.00%
Discount rate	14.00%
Average [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Expected prepayment	11.00%
Discount rate	10.00%