Business Combinations (Detail) $ in Thousands				3 Months Ended								12 Months Ended
		Dec. 01, 2015 USD ($) Branch shares	Nov. 01, 2014 USD ($) Branch shares	Dec. 31, 2015 USD ($) shares	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) shares	Sep. 30, 2014 USD ($) shares	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($)
Assets acquired:
Goodwill	[1]			$ 686,339				$ 575,892				$ 686,339	$ 575,892	$ 428,234
Deposits:
Shares of common stock authorized | shares				332,023,233				332,023,233				332,023,233	332,023,233
Charge within income tax expense				$ (10,987)	$ 10,179	$ 12,474	$ 12,272	$ 7,827	$ 10,654	$ 11,751	$ 830	$ 23,938	$ 31,062	$ 46,979
Core Deposits [Member]
Deposits:
CDI amortization												11 years
CNL Bancshares, Inc [Member]
Business Acquisition [Line Items]
Assets acquired		$ 1,550,350
Loans acuired		825,000
Deposits acquired		$ 1,200,000
Conversion ratio for shares issued		0.705
Total consideration for acquisition		$ 230,000
Shares issued in acquisition | shares		20,600,000
Merger expenses												$ 1,800
Assets acquired:
Cash and cash equivalents		$ 201,025
Marketable securities		327,264
Total loans		825,465
Premises and equipment		8,550
Bank owned life insurance		5,090
Accrued interest receivable		3,741
Goodwill		109,991
Other intangible assets		19,330
Other assets		49,894
Total assets acquired		1,550,350
Deposits:
Non-interest bearing		501,714
Savings, NOW and money market		562,187
Time		103,874
Total deposits		1,167,775
Short-term borrowings		57,087
Long-term borrowings		90,738
Accrued expenses and other liabilities		5,148
Total liabilities assumed		1,320,748
Common stock issued in acquisition		$ 229,602
Charge within income tax expense												$ 3,300
CNL Bancshares, Inc [Member] | Florida [Member]
Business Acquisition [Line Items]
Number of branches acquired | Branch		16
First United Bancorp, Inc. [Member]
Business Acquisition [Line Items]
Assets acquired			$ 1,700,000
Conversion ratio for shares issued			0.89
Total consideration for acquisition			$ 300,000
Shares issued in acquisition | shares			30,700,000
Merger expenses													$ 2,600
Assets acquired:
Total assets acquired			$ 1,700,000
Deposits:
Loans			1,200,000
Total deposits			1,400,000
Cash portion of consideration			$ 8,900
Shares of common stock authorized | shares									100,000,000
Charge within income tax expense								$ 7,600
First United Bancorp, Inc. [Member] | Florida [Member]
Business Acquisition [Line Items]
Number of branches acquired | Branch			20
First United Bancorp, Inc. [Member] | Core Deposits [Member]
Deposits:
CDI amortization			11 years

[1] Valley’s Wealth Management Division is comprised of trust, asset management and insurance services. This reporting unit is included in the Consumer Lending segment for financial reporting purposes.