Loans - Loans Held-for-Investment and Current Period Gross Charge-Offs, Excluding PCD Loans, Net of Deferred Fees and Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Financing Receivable, Allowance for Credit Loss [Line Items]
Total	$ 3,900,346		$ 3,900,346		$ 4,022,224
Current-period gross charge-offs
Total	827	$ 2,355	4,977	$ 4,978
Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	146,764		146,764		115,930
Year Two	117,228		117,228		227,102
Year Three	223,948		223,948		869,173
Year Four	841,631		841,631		819,284
Year Five	782,269		782,269		544,689
Prior	1,602,980		1,602,980		1,279,905
Revolving Loans	177,108		177,108		156,968
Total	3,891,928		3,891,928		4,013,051
Current-period gross charge-offs
Current Fiscal Year			0		0
Year Two			67		387
Year Three			717		3,249
Year Four			1,942		2,966
Year Five			1,112		73
Prior			796		334
Revolving Loans			0		0
Total	484	2,355	4,634	4,978	7,009
Real estate loans: | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	136,809		136,809		95,607
Year Two	100,668		100,668		210,831
Year Three	207,148		207,148		848,649
Year Four	825,125		825,125		804,297
Year Five	770,253		770,253		541,640
Prior	1,595,782		1,595,782		1,273,078
Revolving Loans	92,886		92,886		73,359
Total	3,728,671		3,728,671		3,847,461
Real estate loans: | Multifamily | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	41,319		41,319		4,881
Year Two	4,835		4,835		86,169
Year Three	84,526		84,526		594,887
Year Four	577,495		577,495		630,083
Year Five	608,725		608,725		451,086
Prior	1,123,278		1,123,278		829,885
Revolving Loans	327		327		493
Total	2,440,505		2,440,505		2,597,484
Current-period gross charge-offs
Current Fiscal Year					0
Year Two					0
Year Three					0
Year Four					0
Year Five					0
Prior					136
Revolving Loans					0
Total					136
Real estate loans: | Multifamily | Pass | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	41,319		41,319		4,881
Year Two	4,835		4,835		86,169
Year Three	84,526		84,526		594,887
Year Four	577,495		577,495		628,886
Year Five	607,551		607,551		449,955
Prior	1,113,860		1,113,860		819,582
Revolving Loans	327		327		493
Total	2,429,913		2,429,913		2,584,853
Real estate loans: | Multifamily | Special mention | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	0		0		0
Year Two	0		0		0
Year Three	0		0		0
Year Four	0		0		1,197
Year Five	1,174		1,174		1,131
Prior	0		0		1,445
Revolving Loans	0		0		0
Total	1,174		1,174		3,773
Real estate loans: | Multifamily | Substandard | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	0		0		0
Year Two	0		0		0
Year Three	0		0		0
Year Four	0		0		0
Year Five	0		0		0
Prior	9,418		9,418		8,858
Revolving Loans	0		0		0
Total	9,418		9,418		8,858
Real estate loans: | Commercial mortgage | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	55,176		55,176		63,034
Year Two	62,070		62,070		87,164
Year Three	85,926		85,926		195,575
Year Four	191,183		191,183		149,231
Year Five	138,421		138,421		63,915
Prior	359,230		359,230		329,389
Revolving Loans	2,517		2,517		1,493
Total	894,523		894,523		889,801
Real estate loans: | Commercial mortgage | Pass | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	55,176		55,176		63,034
Year Two	62,070		62,070		87,164
Year Three	85,926		85,926		195,575
Year Four	191,183		191,183		149,231
Year Five	138,421		138,421		61,214
Prior	339,810		339,810		309,280
Revolving Loans	2,230		2,230		1,200
Total	874,816		874,816		866,698
Real estate loans: | Commercial mortgage | Special mention | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	0		0		0
Year Two	0		0		0
Year Three	0		0		0
Year Four	0		0		0
Year Five	0		0		2,701
Prior	8,112		8,112		9,297
Revolving Loans	0		0		0
Total	8,112		8,112		11,998
Real estate loans: | Commercial mortgage | Substandard | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	0		0		0
Year Two	0		0		0
Year Three	0		0		0
Year Four	0		0		0
Year Five	0		0		0
Prior	11,308		11,308		10,812
Revolving Loans	287		287		293
Total	11,595		11,595		11,105
Real estate loans: | One-to-four family residential mortgage | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	18,042		18,042		8,929
Year Two	17,017		17,017		6,597
Year Three	11,259		11,259		23,452
Year Four	21,520		21,520		11,728
Year Five	11,489		11,489		6,547
Prior	86,350		86,350		92,044
Revolving Loans	292		292		920
Total	165,969		165,969		150,217
Current-period gross charge-offs
Total	0	0	0	0
Real estate loans: | One-to-four family residential mortgage | Pass | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	18,042		18,042		8,929
Year Two	17,017		17,017		6,597
Year Three	11,259		11,259		23,452
Year Four	21,520		21,520		11,728
Year Five	11,489		11,489		6,547
Prior	85,003		85,003		91,404
Revolving Loans	292		292		920
Total	164,622		164,622		149,577
Real estate loans: | One-to-four family residential mortgage | Substandard | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	0		0		0
Year Two	0		0		0
Year Three	0		0		0
Year Four	0		0		0
Year Five	0		0		0
Prior	1,347		1,347		640
Revolving Loans	0		0		0
Total	1,347		1,347		640
Real estate loans: | Home equity and lines of credit | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	12,013		12,013		15,231
Year Two	13,129		13,129		19,647
Year Three	16,002		16,002		32,454
Year Four	29,554		29,554		12,630
Year Five	11,618		11,618		6,522
Prior	21,243		21,243		17,125
Revolving Loans	89,750		89,750		70,453
Total	193,309		193,309		174,062
Current-period gross charge-offs
Total	0	0	0	0
Real estate loans: | Home equity and lines of credit | Pass | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	12,013		12,013		15,231
Year Two	13,129		13,129		19,647
Year Three	15,801		15,801		31,378
Year Four	28,058		28,058		12,209
Year Five	11,074		11,074		6,499
Prior	21,061		21,061		16,966
Revolving Loans	89,750		89,750		70,453
Total	190,886		190,886		172,383
Real estate loans: | Home equity and lines of credit | Special mention | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	0		0		0
Year Two	0		0		0
Year Three	0		0		68
Year Four	66		66		0
Year Five	0		0		0
Prior	7		7		0
Revolving Loans	0		0		0
Total	73		73		68
Real estate loans: | Home equity and lines of credit | Substandard | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	0		0		0
Year Two	0		0		0
Year Three	201		201		1,008
Year Four	1,430		1,430		421
Year Five	544		544		23
Prior	175		175		159
Revolving Loans	0		0		0
Total	2,350		2,350		1,611
Real estate loans: | Construction and land | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	10,259		10,259		3,532
Year Two	3,617		3,617		11,254
Year Three	9,435		9,435		2,281
Year Four	5,373		5,373		625
Year Five	0		0		13,570
Prior	5,681		5,681		4,635
Revolving Loans	0		0		0
Total	34,365		34,365		35,897
Current-period gross charge-offs
Total	0	0	0	0
Real estate loans: | Construction and land | Pass | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	10,259		10,259		3,532
Year Two	3,617		3,617		11,254
Year Three	9,435		9,435		2,281
Year Four	5,373		5,373		625
Year Five	0		0		13,570
Prior	5,681		5,681		4,635
Revolving Loans	0		0		0
Total	34,365		34,365		35,897
Commercial and industrial | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	8,810		8,810		18,227
Year Two	16,560		16,560		16,271
Year Three	16,800		16,800		20,524
Year Four	16,506		16,506		14,987
Year Five	12,016		12,016		3,049
Prior	7,185		7,185		6,811
Revolving Loans	84,176		84,176		83,556
Total	162,053		162,053		163,425
Current-period gross charge-offs
Current Fiscal Year			0		0
Year Two			67		387
Year Three			717		3,249
Year Four			1,942		2,966
Year Five			1,112		73
Prior			795		198
Revolving Loans			0		0
Total	483	2,355	4,633	4,842	6,873
Commercial and industrial | Pass | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	8,810		8,810		15,733
Year Two	14,021		14,021		14,768
Year Three	13,003		13,003		19,043
Year Four	15,443		15,443		13,539
Year Five	10,612		10,612		2,977
Prior	6,750		6,750		6,680
Revolving Loans	83,344		83,344		82,552
Total	151,983		151,983		155,292
Commercial and industrial | Special mention | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	0		0		0
Year Two	0		0		770
Year Three	610		610		264
Year Four	0		0		168
Year Five	0		0		0
Prior	0		0		0
Revolving Loans	0		0		0
Total	610		610		1,202
Commercial and industrial | Substandard | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	0		0		2,494
Year Two	2,539		2,539		733
Year Three	3,187		3,187		1,217
Year Four	1,063		1,063		1,280
Year Five	1,404		1,404		72
Prior	435		435		131
Revolving Loans	832		832		1,004
Total	9,460		9,460		6,931
Other loans | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	1,145		1,145		2,096
Year Two	0		0		0
Year Three	0		0		0
Year Four	0		0		0
Year Five	0		0		0
Prior	13		13		16
Revolving Loans	46		46		53
Total	1,204		1,204		2,165
Current-period gross charge-offs
Current Fiscal Year			0
Year Two			0
Year Three			0
Year Four			0
Year Five			0
Prior			1
Revolving Loans			0
Total	1	$ 0	1	$ 0
Other loans | Pass | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	1,145		1,145		2,096
Year Two	0		0		0
Year Three	0		0		0
Year Four	0		0		0
Year Five	0		0		0
Prior	10		10		11
Revolving Loans	46		46		53
Total	1,201		1,201		2,160
Other loans | Substandard | Financial Asset, Other than Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Line Items]
Current Fiscal Year	0		0		0
Year Two	0		0		0
Year Three	0		0		0
Year Four	0		0		0
Year Five	0		0		0
Prior	3		3		5
Revolving Loans	0		0		0
Total	$ 3		$ 3		$ 5