Derivative and Hedging Activities - Offsetting of Derivative Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Gross Amount	$ 100,817	$ 51,605
Gross Amounts Offset in the Balance Sheet, Derivative Liabilities	0	0
Net Amount Presented in the Balance Sheet	100,817	51,605
Subject to Master Netting Arrangement [Member]
Derivatives, Fair Value [Line Items]
Net Amount Presented in the Balance Sheet	100,351	51,453
Subject to Master Netting Arrangement [Member] | Interest Rate Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Amount	1,669	962
Gross Amounts Offset in the Balance Sheet, Derivative Liabilities	0	0
Net Amount Presented in the Balance Sheet	1,669	962
Subject to Master Netting Arrangement [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Gross Amount	98,682	50,491
Gross Amounts Offset in the Balance Sheet, Derivative Liabilities	0	0
Net Amount Presented in the Balance Sheet	98,682	50,491
Not Subject to Master Netting Arrangement [Member]
Derivatives, Fair Value [Line Items]
Net Amount Presented in the Balance Sheet	466	152
Not Subject to Master Netting Arrangement [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Gross Amount		1
Gross Amounts Offset in the Balance Sheet, Derivative Liabilities	0	0
Net Amount Presented in the Balance Sheet		1
Not Subject to Master Netting Arrangement [Member] | Credit Risk Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Amount	407	133
Gross Amounts Offset in the Balance Sheet, Derivative Liabilities	0	0
Net Amount Presented in the Balance Sheet	407	133
Not Subject to Master Netting Arrangement [Member] | Equity Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Amount	59	18
Gross Amounts Offset in the Balance Sheet, Derivative Liabilities	0	0
Net Amount Presented in the Balance Sheet	$ 59	$ 18