Loans Receivable, Net - Credit Quality Indicators for RRE and Consumer Loans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Credit Quality Indicators By Origination
Gross Charge-Offs	$ 3,976	$ 3,201	$ 12,406	$ 10,284
Total	17,181,187		17,181,187		$ 16,198,082
Residential real estate
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		5
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		15
Gross Charge-Offs, Revolving loans			0		0
Gross Charge-Offs	0	0	0	20	20
Term loans originated current fiscal year	134,710		134,710		234,568
Term loans originated fiscal year before current fiscal year	292,783		292,783		673,782
Term loans originated two years before current fiscal year	664,274		664,274		495,645
Term loans originated three years before current fiscal year	467,136		467,136		99,199
Term loans originated four years before current fiscal year	93,073		93,073		42,054
Term loans originated five years before current fiscal year	185,721		185,721		158,828
Revolving loans	0		0		468
Total	1,837,697		1,837,697		1,704,544
Residential real estate | Performing
Credit Quality Indicators By Origination
Term loans originated current fiscal year	134,389		134,389		233,753
Term loans originated fiscal year before current fiscal year	292,088		292,088		671,196
Term loans originated two years before current fiscal year	663,051		663,051		495,645
Term loans originated three years before current fiscal year	466,558		466,558		99,199
Term loans originated four years before current fiscal year	93,073		93,073		42,054
Term loans originated five years before current fiscal year	180,462		180,462		153,489
Revolving loans	0		0		468
Total	1,829,621		1,829,621		1,695,804
Residential real estate | 30-89 Days Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	321		321		815
Term loans originated fiscal year before current fiscal year	174		174		2,586
Term loans originated two years before current fiscal year	467		467		0
Term loans originated three years before current fiscal year	0		0		0
Term loans originated four years before current fiscal year	0		0		0
Term loans originated five years before current fiscal year	1,792		1,792		2,670
Revolving loans	0		0		0
Total	2,754		2,754		6,071
Residential real estate | Non-Accrual and 90 Days or More Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0		0		0
Term loans originated fiscal year before current fiscal year	521		521		0
Term loans originated two years before current fiscal year	756		756		0
Term loans originated three years before current fiscal year	578		578		0
Term loans originated four years before current fiscal year	0		0		0
Term loans originated five years before current fiscal year	3,467		3,467		2,669
Revolving loans	0		0		0
Total	5,322		5,322		2,669
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			17		0
Gross Charge-Offs, originated two years before current fiscal year			0		48
Gross Charge-Offs, originated three years before current fiscal year			0		50
Gross Charge-Offs, originated four years before current fiscal year			0		0
Gross Charge-Offs, Prior			10		31
Gross Charge-Offs, Revolving loans			0		0
Gross Charge-Offs	2	0	27	102	129
Term loans originated current fiscal year	211		211		0
Term loans originated fiscal year before current fiscal year	1,165		1,165		20
Term loans originated two years before current fiscal year	2,102		2,102		0
Term loans originated three years before current fiscal year	893		893		21
Term loans originated four years before current fiscal year	83		83		178
Term loans originated five years before current fiscal year	4,558		4,558		5,492
Revolving loans	922,428		922,428		882,302
Total	931,440		931,440		888,013
Home equity | Performing
Credit Quality Indicators By Origination
Term loans originated current fiscal year	211		211		0
Term loans originated fiscal year before current fiscal year	1,165		1,165		20
Term loans originated two years before current fiscal year	2,102		2,102		0
Term loans originated three years before current fiscal year	893		893		21
Term loans originated four years before current fiscal year	83		83		178
Term loans originated five years before current fiscal year	4,439		4,439		5,277
Revolving loans	914,883		914,883		875,735
Total	923,776		923,776		881,231
Home equity | 30-89 Days Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0		0		0
Term loans originated fiscal year before current fiscal year	0		0		0
Term loans originated two years before current fiscal year	0		0		0
Term loans originated three years before current fiscal year	0		0		0
Term loans originated four years before current fiscal year	0		0		0
Term loans originated five years before current fiscal year	33		33		11
Revolving loans	4,665		4,665		4,522
Total	4,698		4,698		4,533
Home equity | Non-Accrual and 90 Days or More Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	0		0		0
Term loans originated fiscal year before current fiscal year	0		0		0
Term loans originated two years before current fiscal year	0		0		0
Term loans originated three years before current fiscal year	0		0		0
Term loans originated four years before current fiscal year	0		0		0
Term loans originated five years before current fiscal year	86		86		204
Revolving loans	2,880		2,880		2,045
Total	2,966		2,966		2,249
Other consumer
Credit Quality Indicators By Origination
Gross Charge-Offs, originated current fiscal year			6,156		7,801
Gross Charge-Offs, originated fiscal year before current fiscal year			325		715
Gross Charge-Offs, originated two years before current fiscal year			323		170
Gross Charge-Offs, originated three years before current fiscal year			209		85
Gross Charge-Offs, originated four years before current fiscal year			24		73
Gross Charge-Offs, Prior			98		131
Gross Charge-Offs, Revolving loans			0		0
Gross Charge-Offs	2,518	$ 2,344	7,135	$ 6,648	8,975
Term loans originated current fiscal year	96,566		96,566		139,295
Term loans originated fiscal year before current fiscal year	99,808		99,808		98,630
Term loans originated two years before current fiscal year	71,791		71,791		62,961
Term loans originated three years before current fiscal year	43,649		43,649		29,143
Term loans originated four years before current fiscal year	20,749		20,749		12,335
Term loans originated five years before current fiscal year	22,138		22,138		17,314
Revolving loans	46,457		46,457		40,678
Total	401,158		401,158		400,356
Other consumer | Performing
Credit Quality Indicators By Origination
Term loans originated current fiscal year	94,696		94,696		137,035
Term loans originated fiscal year before current fiscal year	98,939		98,939		97,536
Term loans originated two years before current fiscal year	70,439		70,439		62,107
Term loans originated three years before current fiscal year	42,851		42,851		29,012
Term loans originated four years before current fiscal year	20,681		20,681		12,279
Term loans originated five years before current fiscal year	21,862		21,862		16,664
Revolving loans	45,905		45,905		39,489
Total	395,373		395,373		394,122
Other consumer | 30-89 Days Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	1,804		1,804		2,079
Term loans originated fiscal year before current fiscal year	542		542		870
Term loans originated two years before current fiscal year	1,133		1,133		805
Term loans originated three years before current fiscal year	325		325		119
Term loans originated four years before current fiscal year	22		22		43
Term loans originated five years before current fiscal year	72		72		173
Revolving loans	519		519		1,182
Total	4,417		4,417		5,271
Other consumer | Non-Accrual and 90 Days or More Past Due
Credit Quality Indicators By Origination
Term loans originated current fiscal year	66		66		181
Term loans originated fiscal year before current fiscal year	327		327		224
Term loans originated two years before current fiscal year	219		219		49
Term loans originated three years before current fiscal year	473		473		12
Term loans originated four years before current fiscal year	46		46		13
Term loans originated five years before current fiscal year	204		204		477
Revolving loans	33		33		7
Total	$ 1,368		$ 1,368		$ 963