Loans held-for-sale in non-performing status (Detail) - USD ($)	Jun. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	$ 50,875,000	$ 18,899,000
Commercial Portfolio Segment Member
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	48,969,000	309,000
Commercial Real Estate Construction Financing Receivable Member
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	1,681,000	0
Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	225,000	14,041,000
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Non-accrual loans	$ 0	$ 4,549,000