Parent Company Information - Schedule of Condensed Statements of Financial Condition (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Interest bearing deposits with banks	$ 134,915	$ 463,022
Investment securities available for sale	829,692	807,816
Other assets	576,919	538,495
Total assets	16,156,541	16,012,646
Long-term borrowings	2,792,306	2,697,299
Junior subordinated debentures issued to capital trusts (includes fair value of $ 147,595 at December 31, 2012 for VNB Capital Trust I)	41,089	188,522
Shareholders' equity	1,541,040	1,502,377	1,254,836	1,284,935
Total liabilities and shareholders' equity	16,156,541	16,012,646
Parent Company [Member]
Cash	33,592	4,732
Interest bearing deposits with banks	135	55,135
Investment securities available for sale	4,373	4,779
Investment in subsidiaries	1,682,093	1,652,362
Other assets	13,741	9,738
Total assets	1,733,934	1,726,746
Dividends payable to shareholders	21,957	32,147
Long-term borrowings	121,757
Junior subordinated debentures issued to capital trusts (includes fair value of $ 147,595 at December 31, 2012 for VNB Capital Trust I)	41,089	188,522
Accrued expenses and other liabilities	8,091	3,700
Shareholders' equity	1,541,040	1,502,377
Total liabilities and shareholders' equity	$ 1,733,934	$ 1,726,746