Derivative and Hedging Activities - Derivative Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	$ 100,817	$ 51,605
Subject to Master Netting Arrangement [Member]
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	100,351	51,453
Gross Amount Not Offset in the Balance Sheet Financial Instruments, Derivative Liabilities	34,305	25,371
Gross Amount Not Offset in the Balance Sheet Cash Collateral Pledged, Derivative Liabilities	64,556	24,802
Net Amount, Derivative Liabilities	1,490	1,280
Subject to Master Netting Arrangement [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	1,669	962
Gross Amount Not Offset in the Balance Sheet Financial Instruments, Derivative Liabilities		792
Gross Amount Not Offset in the Balance Sheet Cash Collateral Pledged, Derivative Liabilities	1,669	170
Subject to Master Netting Arrangement [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	98,682	50,491
Gross Amount Not Offset in the Balance Sheet Financial Instruments, Derivative Liabilities	34,305	24,579
Gross Amount Not Offset in the Balance Sheet Cash Collateral Pledged, Derivative Liabilities	62,887	24,632
Net Amount, Derivative Liabilities	$ 1,490	$ 1,280