Discontinued operations - Statements of Income Data (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Interest expense
Total interest expense		$ 127,207	$ 125,532	$ 103,402
Net interest income		19,362	9,105	0
Noninterest income
Noninterest income		3,180,298	3,248,505
Noninterest expense
Income (loss) from continuing operations before income taxes		(1,791,595)	182,300	201,954
Income tax expense (benefit)		(470,962)	34,534	38,915
Income (loss) from continuing operations		(1,424,119)	201,128	243,028
Discontinued operations		(103,486)	53,362	79,989
American Savings Bank (ASB) | Discontinued Operations, Disposed of by Sale
Interest and dividend income
Interest and fees on loans		293,100	276,688	207,830
Interest and dividends on investment securities		55,944	58,095	58,044
Total interest and dividend income		349,044	334,783	265,874
Interest expense
Interest on deposit liabilities		72,727	48,905	7,327
Interest on other borrowings		27,442	33,892	5,974
Total interest expense		100,169	82,797	13,301
Net interest income		248,875	251,986	252,573
Provision for credit losses		(1,963)	10,357	2,037
Net interest income after provision for credit losses		250,838	241,629	250,536
Noninterest income
Gain on sale of real estate		0	495	1,778
Loss on sale of investment securities, net		0	(14,965)	0
Total noninterest income		69,528	45,410	56,972
Noninterest expense
Compensation and employee benefits		126,936	118,297	113,839
Occupancy		21,382	21,703	24,026
Data processing		19,612	20,545	17,681
Services		17,485	13,943	10,679
Equipment		9,914	11,842	10,100
Office supplies, printing and postage		4,085	4,315	4,398
Marketing		3,506	4,001	3,968
Goodwill impairment		82,190	0	0
FDIC insurance		5,992	6,230	3,591
Other expense		15,907	22,762	16,985
Total noninterest expense		307,009	223,638	205,267
Income (loss) from continuing operations before income taxes		13,357	63,401	102,241
Income tax expense (benefit)		1,040	10,039	22,252
Income (loss) from continuing operations	$ 12,317	12,317	53,362	79,989
Loss from the sale of ASB		(118,193)	0	0
Income tax benefit	2,390	2,390	0	0
Discontinued operations	$ (103,486)	(103,486)	53,362	79,989
American Savings Bank (ASB) | Discontinued Operations, Disposed of by Sale | Fees from other financial services
Noninterest income
Noninterest income		20,797	19,034	19,830
American Savings Bank (ASB) | Discontinued Operations, Disposed of by Sale | Fee income on deposit liabilities
Noninterest income
Noninterest income		19,900	19,131	18,762
American Savings Bank (ASB) | Discontinued Operations, Disposed of by Sale | Fee income on other financial products
Noninterest income
Noninterest income		11,798	10,616	10,291
American Savings Bank (ASB) | Discontinued Operations, Disposed of by Sale | Bank-owned life insurance
Noninterest income
Noninterest income		13,079	7,390	2,533
American Savings Bank (ASB) | Discontinued Operations, Disposed of by Sale | Mortgage banking income
Noninterest income
Noninterest income		1,419	910	1,692
American Savings Bank (ASB) | Discontinued Operations, Disposed of by Sale | Other income, net
Noninterest income
Noninterest income		$ 2,535	$ 2,799	$ 2,086