Loans and Allowance for Credit Losses - Additional Information (Details)	3 Months Ended
	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($) loan	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 23, 2020 USD ($)	Jul. 08, 2020 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Premiums and discounts on acquired loans	$ 11,143,000		$ 11,723,000
Net deferred origination and factoring fees	5,477,000		5,349,000
Accrued interest on loans	12,056,000		14,513,000
Allowance for credit losses	41,553,000		42,213,000
Loans	4,724,078,000		4,867,572,000
Pledged loans	1,578,984,000		1,733,917,000
Nonaccrual	12,172,000		15,034,000
Interest earned on nonaccrual loans	0	$ 0
Recorded investments in troubled debt restructurings	3,934,000		4,677,000
Number of defaults on modified loans | loan		2
Recorded investments in troubled debt restructurings		$ 5,841,000
Troubled Debt Restructuring
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	924,000		1,068,000
Nonaccrual	3,245,000		3,912,000
Past Due 90 Days or More
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	55,030,000		46,433,000
Over-Formula Advances | Transport Financial Solutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans					$ 62,200,000	$ 62,200,000
Changes in Allowance for Credit Losses
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses change due to loss drivers	1,017,000
Loans Held for Investment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	41,553,000	48,024,000	42,213,000	$ 95,739,000
Net charge-offs	1,500,000	41,251,000
Credit loss expense	864,000	(6,464,000)
Factored receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer reserves	231,506,000		254,970,000
Loans	1,764,590,000		1,699,537,000
Nonaccrual	0		0
Factored receivables | Past Due 90 Days or More
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	47,719,000		39,134,000
Factored receivables | Over-Formula Advances
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	9,646,000		10,077,000
Net charge-offs		41,265,000
Factored receivables | Over-Formula Advances | Past Due 90 Days or More
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	9,646,000		10,077,000
Factored receivables | Misdirected Payments Receivable | United States Postal Service
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	19,361,000		19,361,000
Factored receivables | Loans Held for Investment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	22,471,000	19,716,000	20,915,000	56,463,000
Credit loss expense	2,235,000	4,718,000
1-4 family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	117,534,000		123,115,000
Nonaccrual	1,609,000		1,683,000
1-4 family residential | Past Due 90 Days or More
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,002,000		1,114,000
1-4 family residential | Real Eatate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential real estate loans in process of foreclosure	301,000		301,000
1-4 family residential | Loans Held for Investment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for credit losses	450,000	631,000	$ 468,000	$ 1,225,000
Credit loss expense	$ (21,000)	$ (678,000)