Derivative Financial Instruments - Classification on the balance sheet for the periods indicated (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Foreign currency exchange contracts - foreign currency loan
Asset Derivatives
Total, Asset Derivatives	$ 18
Asset Derivatives
Asset Derivatives
Derivatives not designated as hedging instruments, Interest rate swaps, Other assets	90,748	$ 141,822
Total, Asset Derivatives	91,238	142,643
Asset Derivatives | Risk participation agreements
Asset Derivatives
Derivatives not designated as hedging instruments, Other assets	391	722
Asset Derivatives | Foreign currency exchange contracts - matched customer book
Asset Derivatives
Derivatives not designated as hedging instruments, Other assets	81	90
Asset Derivatives | Foreign currency exchange contracts - foreign currency loan
Asset Derivatives
Derivatives not designated as hedging instruments, Other assets	18	9
Liability Derivatives
Liability Derivatives
Derivative not designated as hedging instruments, Interest rate swaps, Other liabilities	33,620	42,600
Total, Liability Derivatives	34,216	43,976
Liability Derivatives | Risk participation agreements
Liability Derivatives
Derivatives not designated as hedging instruments, Other liabilities	530	1,230
Liability Derivatives | Foreign currency exchange contracts - matched customer book
Liability Derivatives
Derivatives not designated as hedging instruments, Other liabilities	61	77
Liability Derivatives | Foreign currency exchange contracts - foreign currency loan
Liability Derivatives
Derivatives not designated as hedging instruments, Other liabilities	$ 5	$ 69