Borrowed Funds (Narrative) (Detail) (USD $)	12 Months Ended		12 Months Ended				12 Months Ended				1 Months Ended	12 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Trust II [Member]	Dec. 31, 2012 Trust II [Member]	Dec. 31, 2004 Trust II [Member]	Dec. 31, 2012 Federal Home Loan Bank Advances [Member]	Dec. 31, 2013 Federal Funds Purchased [Member] Minimum [Member]	Dec. 31, 2013 Federal Funds Purchased [Member] Maximum [Member]	Dec. 31, 2013 Securities Sold under Agreements to Repurchase [Member] Minimum [Member]	Dec. 31, 2013 Securities Sold under Agreements to Repurchase [Member] Maximum [Member]	Feb. 28, 2007 Subordinated Notes Payable [Member]	Dec. 31, 2013 Subordinated Notes Payable [Member]	Dec. 31, 2012 Subordinated Notes Payable [Member]	Dec. 31, 2013 Junior Subordinated Deferrable Interest Debenture [Member] Trust II [Member]	Dec. 31, 2012 Junior Subordinated Deferrable Interest Debenture [Member] Trust II [Member]
Borrowed Funds [Line Items]
Federal home loan bank advances						$ 7,000
Federal home loan bank advances, weighted-average rate						6.00%
Short term debt maturity period							1 day	90 days	30 days	90 days
Federal funds purchased	200,000	1,600,000
Securities sold under agreements to repurchase	668,100,000	559,500,000
Subordinated Notes											100,000,000
Subordinated Notes interest rate											5.75%
Maturity date											Feb. 15, 2017
Advances, variable-rate			1.79%	1.86%	1.55%						0.53%	0.77%
LIBOR plus margin					Three-month LIBOR plus a margin of 1.55%						Three-month LIBOR for the related interest period plus 0.53%
Percentage of redemption price												100.00%
Unamortized debt issuance cost related to note												370,000	490,000	1,200,000	1,200,000
Junior subordinated deferrable interest debentures	123,712,000	123,712,000												123,712,000.000	123,712,000
Trust preferred securities, issued			120,000,000		120,000,000
Maturity date of trust preferred securities			March 1, 2034
Common equity securities	$ 144,486,000													$ 3,700,000.0
Maximum allowable percentage of core capital included in Tier 1 Capital by Most Bank Holding Companies	25.00%
Maximum allowable percentage of core capital included in Tier 1 Capital by Large International Bank Holding Companies	15.00%