Business, Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details)							1 Months Ended	3 Months Ended				6 Months Ended
	Jul. 19, 2023 $ / shares	Apr. 19, 2023 $ / shares	Jan. 18, 2023 $ / shares	Jan. 13, 2023 USD ($)	Apr. 13, 2022 $ / shares	Jan. 19, 2022 $ / shares	Jan. 31, 2022 USD ($) shares	Jun. 30, 2023 USD ($) $ / shares shares	Mar. 31, 2023 shares	Jun. 30, 2022 USD ($) $ / shares shares	Mar. 31, 2022 shares	Jun. 30, 2023 USD ($) subsidiary $ / shares shares	Jun. 30, 2022 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares	Dec. 19, 2022 USD ($)
Class of Stock [Line Items]
Number of subsidiaries | subsidiary												3
Common stock, par value (in dollars per share) | $ / shares								$ 0.10				$ 0.10		$ 0.10
Professional and other services fees								$ 7,415,000		$ 4,734,000		$ 15,043,000	$ 10,873,000
Repurchase of common stock - Class A												(2,225,000)	(72,060,000)
Dividends declared (in dollars per share) | $ / shares		$ 0.09	$ 0.09		$ 0.09	$ 0.09
Goodwill								20,525,000				20,525,000		$ 19,506,000
Impairment on investment carried at cost								2,000,000				1,963,000	0
Employee Stock
Class of Stock [Line Items]
Share-based compensation expense								100,000				200,000
F&B Acquisition Group LLC
Class of Stock [Line Items]
Payments to acquire businesses				$ 2,000,000
Loans held for sale at fair value				1,000,000
Goodwill				$ 1,000,000
Subsequent Event
Class of Stock [Line Items]
Dividends declared (in dollars per share) | $ / shares	$ 0.09
Multi-Year Outsourcing Agreement
Class of Stock [Line Items]
Severance expense								2,200,000		700,000		2,400,000	1,400,000
Professional and other services fees								2,100,000		100,000		4,800,000	1,300,000
Business exit costs								1,600,000				2,000,000
Impairments of operating lease ROU asset										1,600,000			1,600,000
Contract Termination | Multi-Year Outsourcing Agreement
Class of Stock [Line Items]
Restructuring costs								1,600,000		$ 2,800,000		1,600,000	$ 6,800,000
Facility Closing | Multi-Year Outsourcing Agreement
Class of Stock [Line Items]
Capitalized computer software, impairments								$ 1,400,000				$ 1,400,000
Class A Common Stock
Class of Stock [Line Items]
Common stock, par value (in dollars per share) | $ / shares								$ 0.10				$ 0.10
Treasury stock (in shares) | shares								0		0		0	0
Class A Common Stock | Common Stock
Class of Stock [Line Items]
Repurchase of Class A common stock (in shares) | shares								(95,262)	(22,403)	(611,525)	(1,643,480)	(117,665)
Treasury stock acquired (in dollars per share) | $ / shares								$ 17.42				$ 18.91
Repurchase of common stock - Class A								$ (1,700,000)				$ (2,200,000)
Stock issued for employee stock purchase plan (in shares) | shares								30,557				30,557
Class A Common Stock | 2023 Class A Common Stock Repurchase Program Member
Class of Stock [Line Items]
Stock repurchase program, authorized amount															$ 25,000,000
Class A Common Stock | 2021 Class A Common Stock Repurchase Program
Class of Stock [Line Items]
Stock repurchase program, authorized amount							$ 50,000,000
Treasury stock, acquired (in shares) | shares							652,118
Treasury stock acquired							$ 22,100,000
Class A Common Stock | 2022 Class A Common Stock Repurchase Program
Class of Stock [Line Items]
Stock repurchase program, authorized amount							$ 50,000,000
Treasury stock acquired (in dollars per share) | $ / shares										$ 28.19			$ 31.14
Treasury stock, acquired (in shares) | shares										611,525			1,602,887
Treasury stock acquired								$ 17,200,000				$ 49,900,000
Amerant Bank, N.A
Class of Stock [Line Items]
Ownership percentage of subsidiary								100.00%				100.00%