Loans Receivable, Net - Credit Quality Indicators for RRE, Home Equity and Consumer Loans (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Credit Quality Indicators By Origination
Gross Charge-Offs	$ 3,897	$ 4,295
Total	17,218,518		$ 17,261,849
Residential real estate
Credit Quality Indicators By Origination
Gross Charge-Offs, originated current fiscal year	0		40
Gross Charge-Offs, originated fiscal year before current fiscal year	0		0
Gross Charge-Offs, originated two years before current fiscal year	0		0
Gross Charge-Offs, originated three years before current fiscal year	0		0
Gross Charge-Offs, originated four years before current fiscal year	0		0
Gross Charge-Offs, Prior	0		0
Gross Charge-Offs, Revolving loans	0		0
Gross Charge-Offs	0	0	40
Term loans originated current fiscal year	20,676		211,519
Term loans originated fiscal year before current fiscal year	229,810		267,000
Term loans originated two years before current fiscal year	251,919		655,918
Term loans originated three years before current fiscal year	642,493		455,196
Term loans originated four years before current fiscal year	443,136		90,752
Term loans originated five years before current fiscal year	262,045		178,544
Revolving loans	0		0
Total	1,850,079		1,858,929
Residential real estate | Performing
Credit Quality Indicators By Origination
Term loans originated current fiscal year	20,676		210,806
Term loans originated fiscal year before current fiscal year	228,650		264,817
Term loans originated two years before current fiscal year	247,981		652,993
Term loans originated three years before current fiscal year	639,552		452,628
Term loans originated four years before current fiscal year	439,999		90,649
Term loans originated five years before current fiscal year	254,126		173,003
Revolving loans	0		0
Total	1,830,984		1,844,896
Residential real estate | 30-89 Days Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0		0
Term loans originated fiscal year before current fiscal year	463		1,407
Term loans originated two years before current fiscal year	3,252		2,566
Term loans originated three years before current fiscal year	2,941		959
Term loans originated four years before current fiscal year	719		0
Term loans originated five years before current fiscal year	3,487		667
Revolving loans	0		0
Total	10,862		5,599
Residential real estate | Non-Accrual and 90 Days or More Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0		713
Term loans originated fiscal year before current fiscal year	697		776
Term loans originated two years before current fiscal year	686		359
Term loans originated three years before current fiscal year	0		1,609
Term loans originated four years before current fiscal year	2,418		103
Term loans originated five years before current fiscal year	4,432		4,874
Revolving loans	0		0
Total	8,233		8,434
Home equity
Credit Quality Indicators By Origination
Gross Charge-Offs, originated current fiscal year	0		0
Gross Charge-Offs, originated fiscal year before current fiscal year	0		17
Gross Charge-Offs, originated two years before current fiscal year	0		8
Gross Charge-Offs, originated three years before current fiscal year	0		0
Gross Charge-Offs, originated four years before current fiscal year	0		0
Gross Charge-Offs, Prior	0		106
Gross Charge-Offs, Revolving loans	0		0
Gross Charge-Offs	0	25	131
Term loans originated current fiscal year	0		219
Term loans originated fiscal year before current fiscal year	147		1,072
Term loans originated two years before current fiscal year	1,060		1,858
Term loans originated three years before current fiscal year	1,833		780
Term loans originated four years before current fiscal year	771		78
Term loans originated five years before current fiscal year	4,034		4,353
Revolving loans	912,287		922,634
Total	920,132		930,994
Home equity | Performing
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0		219
Term loans originated fiscal year before current fiscal year	147		1,045
Term loans originated two years before current fiscal year	1,035		1,858
Term loans originated three years before current fiscal year	1,833		780
Term loans originated four years before current fiscal year	771		78
Term loans originated five years before current fiscal year	4,001		4,264
Revolving loans	902,088		915,614
Total	909,875		923,858
Home equity | 30-89 Days Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0		0
Term loans originated fiscal year before current fiscal year	0		0
Term loans originated two years before current fiscal year	0		0
Term loans originated three years before current fiscal year	0		0
Term loans originated four years before current fiscal year	0		0
Term loans originated five years before current fiscal year	3		4
Revolving loans	6,802		3,660
Total	6,805		3,664
Home equity | Non-Accrual and 90 Days or More Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0		0
Term loans originated fiscal year before current fiscal year	0		27
Term loans originated two years before current fiscal year	25		0
Term loans originated three years before current fiscal year	0		0
Term loans originated four years before current fiscal year	0		0
Term loans originated five years before current fiscal year	30		85
Revolving loans	3,397		3,360
Total	3,452		3,472
Other consumer
Credit Quality Indicators By Origination
Gross Charge-Offs, originated current fiscal year	2,040		8,456
Gross Charge-Offs, originated fiscal year before current fiscal year	35		431
Gross Charge-Offs, originated two years before current fiscal year	94		467
Gross Charge-Offs, originated three years before current fiscal year	99		238
Gross Charge-Offs, originated four years before current fiscal year	37		34
Gross Charge-Offs, Prior	56		155
Gross Charge-Offs, Revolving loans	0		0
Gross Charge-Offs	2,361	$ 2,338	9,781
Term loans originated current fiscal year	32,177		116,312
Term loans originated fiscal year before current fiscal year	98,513		89,684
Term loans originated two years before current fiscal year	80,861		64,808
Term loans originated three years before current fiscal year	57,496		36,755
Term loans originated four years before current fiscal year	31,645		18,648
Term loans originated five years before current fiscal year	36,214		20,014
Revolving loans	37,115		42,457
Total	374,021		388,678
Other consumer | Performing
Credit Quality Indicators By Origination
Term loans originated current fiscal year	30,687		114,164
Term loans originated fiscal year before current fiscal year	97,913		89,218
Term loans originated two years before current fiscal year	80,114		63,843
Term loans originated three years before current fiscal year	56,698		36,233
Term loans originated four years before current fiscal year	30,872		18,601
Term loans originated five years before current fiscal year	35,740		19,738
Revolving loans	36,731		42,039
Total	368,755		383,836
Other consumer | 30-89 Days Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	1,490		2,139
Term loans originated fiscal year before current fiscal year	538		262
Term loans originated two years before current fiscal year	604		665
Term loans originated three years before current fiscal year	504		261
Term loans originated four years before current fiscal year	521		41
Term loans originated five years before current fiscal year	220		103
Revolving loans	281		409
Total	4,158		3,880
Other consumer | Non-Accrual and 90 Days or More Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0		9
Term loans originated fiscal year before current fiscal year	62		204
Term loans originated two years before current fiscal year	143		300
Term loans originated three years before current fiscal year	294		261
Term loans originated four years before current fiscal year	252		6
Term loans originated five years before current fiscal year	254		173
Revolving loans	103		9
Total	$ 1,108		$ 962