Business Combination - Schedule of Pro Forma Information (Details) - Luther Burbank - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Business Acquisition [Line Items]
Net-interest income	$ 531,398	$ 646,731
Non-interest income	47,493	40,965
Net income	$ 142,921	$ 238,473