Allowance for Credit Losses - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Jan. 01, 2020	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses attributable to restructured loans	$ 168,098	$ 50,814	$ 168,098	$ 50,814	$ 145,387		$ 52,162	$ 50,059	$ 49,026
Provision for credit losses on loans	23,100	1,700	76,350	4,100
Cumulative Effect, Period Of Adoption, Adjustment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses attributable to restructured loans						$ 42,484	42,484
Real estate – construction:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses attributable to restructured loans	13,819	5,127	13,819	5,127	12,538		5,029	$ 5,302	$ 4,755
Provision for credit losses on loans	1,386	$ (175)	5,922	$ 365
Real estate – construction: | Cumulative Effect, Period Of Adoption, Adjustment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses attributable to restructured loans							3,505
Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses attributable to restructured loans	1,832		1,832		$ 1,812		910
Provision for credit losses on loans	$ 187		$ 558
Lease financing | Cumulative Effect, Period Of Adoption, Adjustment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan losses attributable to restructured loans							$ 521
Minimum | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maturity term			2 years
Minimum | Residential | Real estate – construction:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maturity term			9 months
Minimum | Commercial | Real estate – construction:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maturity term			24 months
Maximum | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maturity term			5 years
Maximum | Residential | Real estate – construction:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maturity term			12 months
Maximum | Commercial | Real estate – construction:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maturity term			36 months