Balance Sheet Offsetting - Financial Instruments Eligible for Offset Consolidated Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Gross Amount Recognized, Derivatives, Financial Assets	$ 28,141	$ 11,111
Gross Amount Offset, Derivatives, Financial assets	0	0
Net Amount Recognized, Derivatives, Financial assets	28,141	11,111
Gross Amount Recognized, Resell agreements, Financial assets	7,903	0
Gross Amount Offset, Resell agreements, Financial assets	0	0
Net Amount Recognized, Resell agreements, Financial assets	7,903	0
Gross Amount Recognized, Financial assets	36,044	11,111
Gross Amount Offset, Financial assets	0	0
Net Amount Recognized, Financial assets	36,044	11,111
Gross Amount Recognized, Derivatives, Financial Liabilities	224,432	69,323
Gross Amount Offset, Derivatives, Financial liabilities	0	0
Net Amount Recognized, Derivatives, Financial liabilities	224,432	69,323
Gross Amount Recognized, Repurchase agreements, Financial liabilities	2,200,029	2,068,147
Gross Amount Offset, Repurchase agreements, Financial liabilities	0	0
Net Amount Recognized, Repurchase agreements, Financial liabilities	2,200,029	2,068,147
Gross Amount Recognized, Financial liabilities	2,424,461	2,137,470
Gross Amount Offset, Financial liabilities	0	0
Net Amount Recognized, Financial Liabilities	2,424,461	2,137,470
Loan/lease interest rate swaps and caps [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Gross Amount Recognized, Derivatives, Financial Assets	3,556	1,241
Gross Amount Offset, Derivatives, Financial assets	0	0
Net Amount Recognized, Derivatives, Financial assets	3,556	1,241
Commodity swaps and options [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Gross Amount Recognized, Derivatives, Financial Assets	24,583	9,870
Gross Amount Offset, Derivatives, Financial assets	0	0
Net Amount Recognized, Derivatives, Financial assets	24,583	9,870
Gross Amount Recognized, Derivatives, Financial Liabilities	201,499	35,377
Gross Amount Offset, Derivatives, Financial liabilities	0	0
Net Amount Recognized, Derivatives, Financial liabilities	201,499	35,377
Loan/lease interest rate swaps [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Gross Amount Recognized, Derivatives, Financial Liabilities	22,933	33,946
Gross Amount Offset, Derivatives, Financial liabilities	0	0
Net Amount Recognized, Derivatives, Financial liabilities	22,933	$ 33,946
Foreign currency forward contracts [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Gross Amount Recognized, Derivatives, Financial Assets	2
Gross Amount Offset, Derivatives, Financial assets	0
Net Amount Recognized, Derivatives, Financial assets	$ 2