Financial Information - WAFD, Inc.. - Statements of Financial Condition (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Assets
Other assets	$ 581,793	$ 504,652
Total assets	22,474,675	20,772,131
Liabilities
Dividend payable on preferred stock	3,656	3,656	$ 3,656
Total liabilities	20,048,249	18,497,871
Shareholders’ equity
Total shareholders’ equity	2,426,426	2,274,260	$ 2,126,064	$ 2,014,133
Total liabilities and shareholders’ equity	22,474,675	20,772,131
Parent Company
Assets
Cash	74,450	130,502
Other assets	16,171	5,000
Investment in subsidiary	2,340,199	2,143,116
Total assets	2,430,820	2,278,618
Liabilities
Dividend payable on preferred stock	3,656	3,656
Other liabilities	738	702
Total liabilities	4,394	4,358
Shareholders’ equity
Total shareholders’ equity	2,426,426	2,274,260
Total liabilities and shareholders’ equity	$ 2,430,820	$ 2,278,618