Non Traditional Mortgages Portfolio (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Loans and Leases Receivable [Line Items]
Amount	$ 2,396,995	$ 2,446,111	$ 1,627,272
Non Traditional Mortgages
Loans and Leases Receivable [Line Items]
Count	444	478
Amount	269,410	309,597
Percent	100.00%	100.00%
% of NTM to total gross loan portfolio	11.20%	12.70%
Non Traditional Mortgages | Heloc First Liens
Loans and Leases Receivable [Line Items]
Count	167	173
Amount	143,708	147,705
Percent	53.30%	47.60%
Non Traditional Mortgages | Interest-only - first liens
Loans and Leases Receivable [Line Items]
Count	221	244
Amount	105,446	139,867
Percent	39.10%	45.20%
Non Traditional Mortgages | Negative Amortization Loans
Loans and Leases Receivable [Line Items]
Count	35	37
Amount	15,222	16,623
Percent	5.70%	5.40%
Non Traditional Mortgages | First liens
Loans and Leases Receivable [Line Items]
Count	423	454
Amount	264,376	304,195
Percent	98.10%	98.20%
Non Traditional Mortgages | Heloc Second Liens
Loans and Leases Receivable [Line Items]
Count	20	23
Amount	4,921	5,289
Percent	1.80%	1.70%
Non Traditional Mortgages | Interest-only - second liens
Loans and Leases Receivable [Line Items]
Count	1	1
Amount	113	113
Percent	0.10%	0.10%
Non Traditional Mortgages | Second liens
Loans and Leases Receivable [Line Items]
Count	21	24
Amount	5,034	5,402
Percent	1.90%	1.80%
Total Loans and Leases Receivable
Loans and Leases Receivable [Line Items]
Amount	$ 2,396,995	$ 2,446,111