Derivative Instruments and Hedging Activities - Fair Value of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Interest Rate Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Assets, Fair Value	$ 0	$ 0
Derivative Liabilities, Fair Value	25,434	13,932
Other Assets | Derivative Designated as Cash Flow Hedges | Interest Rate Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Assets, Fair Value	0	0
Other Assets | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Assets, Fair Value	18,789	9,295
Other Assets | Not Designated as Hedging Instrument | Residential Mortgage Loan Commitments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Assets, Fair Value	85	45
Other Assets | Not Designated as Hedging Instrument | Interest Rate Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Assets, Fair Value	18,453	9,088
Other Assets | Not Designated as Hedging Instrument | Credit Contract
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Assets, Fair Value	251	162
Other Liabilities | Derivative Designated as Cash Flow Hedges | Interest Rate Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Liabilities, Fair Value	5,695	4,477
Other Liabilities | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Liabilities, Fair Value	19,771	9,455
Other Liabilities | Not Designated as Hedging Instrument | Residential Mortgage Loan Commitments
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Liabilities, Fair Value	0	0
Other Liabilities | Not Designated as Hedging Instrument | Interest Rate Swaps
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Liabilities, Fair Value	19,739	9,455
Other Liabilities | Not Designated as Hedging Instrument | Credit Contract
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Liabilities, Fair Value	$ 32	$ 0