Loans - Loans Held for Sale (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale, at lower of cost or fair value	$ 143,195	$ 0
Mortgage loans held for sale, at fair value	14,905	0
Proceeds from sale of loans held-for-sale	70,000
Amerant Mortgage Inc.
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans held for sale, at fair value	20,800
New York
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for sale, at lower of cost or fair value	49,100
Real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	158,100	0
Real estate loans | Non-owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	110,271	0
Real estate loans | Multi-family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	31,606	0
Real estate loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	141,877	0
Real estate loans | Single-family residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	14,905	0
Real estate loans | Owner-occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	$ 1,318	$ 0