Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Earnings Per Share [Abstract]
Net income before attribution of noncontrolling interest	$ 19,942	$ 14,303
Noncontrolling interest	(244)	(1,076)
Net income attributable to Amerant Bancorp Inc.	$ 20,186	$ 15,379
Basic weighted average shares outstanding (in shares)	33,559,718	34,819,984
Dilutive effect of share-based compensation awards (in shares)	296,276	294,059
Diluted weighted average shares outstanding (in shares)	33,855,994	35,114,043
Basic earnings per common share (in dollars per share)	$ 0.60	$ 0.44
Diluted earnings per common share (in dollars per share)	$ 0.60	$ 0.44
Non-vested shares (in shares)	509,307	526,755