Parent Company Information - Schedule of Condensed Statements of Financial Condition (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash	$ 4,732	$ 42,593
Interest bearing deposits with banks	463,022	6,483
Investment securities available for sale	807,816	566,520
Investment in subsidiaries	1,652,362	1,373,513
Loans	10,842,125	9,527,797
Other assets	538,495	594,382
Total assets	16,012,646	14,252,755
Dividends payable to shareholders	32,147	29,355
Junior subordinated debentures issued to capital trusts (includes fair value of $147,595 at December 31, 2012 and $160,478 at December 31, 2011 for VNB Capital Trust I)	188,522	185,598
Accrued expenses and other liabilities	3,700	2,715
Shareholders' equity	1,502,377	1,254,836	1,284,935	1,243,748
Total liabilities and Shareholders' Equity	$ 16,012,646	$ 14,252,755