Derivative and Hedging Activities - Derivative Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	$ 93,514	$ 51,605
Subject to Master Netting Arrangements [Member]
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	93,116	51,453
Gross Amount Not Offset in the Balance Sheet Financial Instruments, Derivative Liabilities	29,605	25,371
Gross Amount Not Offset in the Balance Sheet Cash Collateral Pledged, Derivative Liabilities	62,448	24,802
Net Amount, Derivative Liabilities	1,063	1,280
Subject to Master Netting Arrangements [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	1,167	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	1,167	170
Subject to Master Netting Arrangements [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Net Amount Presented in the Balance Sheet	91,949	50,491
Gross Amount Not Offset in the Balance Sheet Financial Instruments, Derivative Liabilities	29,605	24,579
Gross Amount Not Offset in the Balance Sheet Cash Collateral Pledged, Derivative Liabilities	61,281	24,632
Net Amount, Derivative Liabilities	$ 1,063	$ 1,280