Consolidated Statements of Changes in Stockholders’ Equity (unaudited) - USD ($) $ in Thousands	Total	Cumulative effect of adoption of ASU No. 2016-13	Balance at January 1, 2023 adjusted for change in accounting principle	Total Amalgamated Financial Corp. Stockholders' Equity	Total Amalgamated Financial Corp. Stockholders' Equity Cumulative effect of adoption of ASU No. 2016-13	Total Amalgamated Financial Corp. Stockholders' Equity Balance at January 1, 2023 adjusted for change in accounting principle	Common Stock	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative effect of adoption of ASU No. 2016-13	Retained Earnings Balance at January 1, 2023 adjusted for change in accounting principle	Accumulated Other Comprehensive Loss, net of income taxes	Treasury Stock, at cost	Noncontrolling Interest
Beginning balance (in shares) at Dec. 31, 2022							30,700,198
Beginning balance at Dec. 31, 2022	$ 508,955	$ (17,825)	$ 491,130	$ 508,822	$ (17,825)	$ 490,997	$ 307	$ 286,947	$ 330,275	$ (17,825)	$ 312,450	$ (108,707)	$ 0	$ 133
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	21,338			21,338					21,338
Repurchase of common stock (in shares)							(128,803)
Repurchase of common stock	(2,425)			(2,425)									(2,425)
Common stock issued under Employee Stock Purchase Plan (in shares)							21,919
Common stock issued under Employee Stock Purchase Plan	388			388				(25)					413
Dividends on common stock, $0.10 per share	(3,115)			(3,115)					(3,115)
Exercise of stock options, net of repurchases (in shares)							6,631
Exercise of stock options, net of repurchases	(91)			(91)				(91)
Restricted stock units vesting, net of repurchases (in shares)							42,354
Restricted stock units vesting, net of repurchases	(494)			(494)				(354)					(140)
Stock-based compensation expense	1,037			1,037				1,037
Other comprehensive income, net of taxes	11,390			11,390								11,390
Ending balance (in shares) at Mar. 31, 2023							30,642,299
Ending balance at Mar. 31, 2023	$ 519,158			519,025			$ 307	287,514	330,673			(97,317)	(2,152)	133
Beginning balance (in shares) at Dec. 31, 2023	30,428,359						30,428,359
Beginning balance at Dec. 31, 2023	$ 585,364			585,231			$ 307	288,232	388,033			(86,004)	(5,337)	133
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	27,249			27,249					27,249
Repurchase of common stock (in shares)							(10,000)
Repurchase of common stock	(285)			(285)									(285)
Common stock issued under Employee Stock Purchase Plan (in shares)							10,175
Common stock issued under Employee Stock Purchase Plan	244			244				60					184
Dividends on common stock, $0.10 per share	$ (3,092)			(3,092)					(3,092)
Exercise of stock options, net of repurchases (in shares)	42,000						24,540
Exercise of stock options, net of repurchases	$ 0							(426)					426
Restricted stock units vesting, net of repurchases (in shares)							57,319
Restricted stock units vesting, net of repurchases	(755)			(755)				(1,749)					994
Stock-based compensation expense	1,081			1,081				1,081
Other comprehensive income, net of taxes	$ 7,132			7,132								7,132
Ending balance (in shares) at Mar. 31, 2024	30,510,393						30,510,393
Ending balance at Mar. 31, 2024	$ 616,938			$ 616,805			$ 307	$ 287,198	$ 412,190			$ (78,872)	$ (4,018)	$ 133