Commitments, Guarantees, and Contingent Liabilities (Detail) - Contractual or Notional Amounts of Financial Instruments - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Commitments to extend credit:
Commercial, industrial, and agricultural		$ 1,303,056	$ 1,299,683
Commercial real estate		366,250	170,573
Home equity		352,114	317,783
Other commitments	[1]	203,121	194,556
Total commitments to extend credit		2,224,541	1,982,595
Standby letters of credit		100,610	110,639
Recourse on assets sold:
Unpaid principal balance of loans sold		196,389	185,910
Carrying value of recourse obligation	[2]	$ 87	$ 155

[1] Other commitments includes installment and overdraft protection program commitments.

[2] Included in other liabilities in the Consolidated Statements of Financial Condition.