Balance Sheet Offsetting - Summary of Valley's Financial Instruments that are Eligible for Offset (Detail) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Offsetting Liabilities
Gross Amounts Recognized		$ 525,752	$ 428,239
Gross Amounts Offset		0	0
Net Amounts Presented, Liabilities		525,752	428,239
Gross Amounts Not Offset, Financial Instruments		(8,942)	(8,504)
Gross Amounts Not Offset, Cash Collateral		(516,810)	(419,735)
Net Amount, Liabilities		0	0
Repurchase agreements
Offsetting Liabilities
Gross Amounts Recognized, Liabilities		475,000	395,000
Gross Amounts Offset, Liabilities		0	0
Securities sold under agreements to repurchase		475,000	395,000
Gross Amounts Not Offset, Financial Instruments		0	0
Gross Amounts Not Offset, Cash Collateral	[1]	(475,000)	(395,000)
Net Amount, Liabilities		0	0
Interest rate caps and swaps
Offsetting Assets
Gross Amounts Recognized		33,570	20,950
Gross Amounts Offset		0	0
Net Amounts Presented, Assets		33,570	20,950
Gross Amounts Not Offset, Financial Instruments		(8,942)	(8,504)
Gross Amounts Not Offset, Cash Collateral		0	0
Net Amount, Assets		24,628	12,446
Offsetting Liabilities
Gross Amounts Recognized		50,752	33,239
Gross Amounts Offset		0	0
Net Amounts Presented, Liabilities		50,752	33,239
Gross Amounts Not Offset, Financial Instruments		(8,942)	(8,504)
Gross Amounts Not Offset, Cash Collateral		(41,810)	(24,735)
Net Amount, Liabilities		$ 0	$ 0

[1] Represents fair value of non-cash pledged investment securities.