Loans Held for Investment - Internal Risk Grading System under ASC 326 (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	$ 189,532		$ 189,532		$ 3,033,849
Fiscal Year before current fiscal year	2,956,366		2,956,366		4,237,198
Two Years before current fiscal year	3,999,162		3,999,162		1,402,650
Three Years before current fiscal year	1,282,063		1,282,063		1,788,312
Four Years before current fiscal year	1,632,127		1,632,127		861,690
Prior	2,660,897		2,660,897		2,206,015
Revolving	925,725		925,725		1,203,904
Revolving Converted to Term During the Period	17,540		17,540		4,606
Total	13,663,412		13,663,412		14,738,224
Current fiscal year charge off			0
One year before current fiscal year charge off			282
Two year before current fiscal year charge off			594
Three year before current fiscal year charge off			196
Four year before current fiscal year charge off			289
Prior year before current fiscal year charge off			5,610
Revolving charge off			679
Revolving Converted to Term During the Period charge off			0
Total	3,986	$ 5,831	7,650	$ 8,130
Loans held for investment	13,610,282		13,610,282		14,676,298
Basis adjustment associated with fair value hedge
Financing Receivable, Credit Quality Indicator [Line Items]
Total	13,663,412		13,663,412		14,738,224
Basis adjustment associated with fair value hedge	53,130		53,130		61,926
Investor loans secured by real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	132,519		132,519		1,948,392
Fiscal Year before current fiscal year	1,969,109		1,969,109		2,954,826
Two Years before current fiscal year	2,834,984		2,834,984		1,034,449
Three Years before current fiscal year	943,834		943,834		1,268,038
Four Years before current fiscal year	1,203,196		1,203,196		590,859
Prior	1,742,394		1,742,394		1,416,489
Revolving	403		403		0
Revolving Converted to Term During the Period	0		0		463
Total	8,826,439		8,826,439		9,213,516
Current fiscal year charge off			0
One year before current fiscal year charge off			0
Two year before current fiscal year charge off			217
Three year before current fiscal year charge off			0
Four year before current fiscal year charge off			0
Prior year before current fiscal year charge off			2,730
Revolving charge off			0
Revolving Converted to Term During the Period charge off			0
Total			2,947
Loans held for investment	8,826,439		8,826,439		9,213,516
Investor loans secured by real estate | CRE non-owner-occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,571,246		2,571,246		2,660,321
Total	2,591	0	2,657	0
Loans held for investment	2,571,246		2,571,246		2,660,321
Investor loans secured by real estate | CRE non-owner-occupied | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	13,775		13,775		523,895
Fiscal Year before current fiscal year	520,853		520,853		607,153
Two Years before current fiscal year	599,620		599,620		208,760
Three Years before current fiscal year	196,597		196,597		347,889
Four Years before current fiscal year	321,542		321,542		308,317
Prior	903,295		903,295		651,593
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	2,555,682		2,555,682		2,647,607
Investor loans secured by real estate | CRE non-owner-occupied | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		0
Fiscal Year before current fiscal year	3,847		3,847		0
Two Years before current fiscal year	2,570		2,570		0
Three Years before current fiscal year	0		0		0
Four Years before current fiscal year	0		0		7,487
Prior	0		0		0
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	6,417		6,417		7,487
Investor loans secured by real estate | CRE non-owner-occupied | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		0
Fiscal Year before current fiscal year	437		437		0
Two Years before current fiscal year	0		0		0
Three Years before current fiscal year	0		0		0
Four Years before current fiscal year	0		0		194
Prior	8,710		8,710		4,570
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		463
Total	9,147		9,147		5,227
Investor loans secured by real estate | Multifamily
Financing Receivable, Credit Quality Indicator [Line Items]
Total	5,788,030		5,788,030		6,112,026
Total	73	0	290	0
Loans held for investment	5,788,030		5,788,030		6,112,026
Investor loans secured by real estate | Multifamily | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	73,440		73,440		1,230,359
Fiscal Year before current fiscal year	1,210,300		1,210,300		2,187,255
Two Years before current fiscal year	2,095,164		2,095,164		786,436
Three Years before current fiscal year	739,051		739,051		889,737
Four Years before current fiscal year	858,898		858,898		263,241
Prior	798,230		798,230		732,808
Revolving	403		403		0
Revolving Converted to Term During the Period	0		0		0
Total	5,775,486		5,775,486		6,089,836
Investor loans secured by real estate | Multifamily | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		0
Fiscal Year before current fiscal year	0		0		0
Two Years before current fiscal year	0		0		0
Three Years before current fiscal year	0		0		12,667
Four Years before current fiscal year	12,544		12,544		0
Prior	0		0		0
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	12,544		12,544		12,667
Investor loans secured by real estate | Multifamily | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year					0
Fiscal Year before current fiscal year					6,057
Two Years before current fiscal year					0
Three Years before current fiscal year					2,723
Four Years before current fiscal year					0
Prior					743
Revolving					0
Revolving Converted to Term During the Period					0
Total					9,523
Investor loans secured by real estate | Construction and land
Financing Receivable, Credit Quality Indicator [Line Items]
Total	428,287		428,287		399,034
Total	0	0	0	0
Loans held for investment	428,287		428,287		399,034
Investor loans secured by real estate | Construction and land | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	45,304		45,304		187,567
Fiscal Year before current fiscal year	227,148		227,148		154,231
Two Years before current fiscal year	137,500		137,500		38,760
Three Years before current fiscal year	7,693		7,693		9,615
Four Years before current fiscal year	4,858		4,858		1,843
Prior	5,784		5,784		7,018
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	428,287		428,287		399,034
Investor loans secured by real estate | SBA secured by real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	38,876		38,876		42,135
Total	0	0	0	70
Loans held for investment	38,876		38,876		42,135
Investor loans secured by real estate | SBA secured by real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		6,571
Fiscal Year before current fiscal year	6,524		6,524		130
Two Years before current fiscal year	130		130		493
Three Years before current fiscal year	493		493		5,407
Four Years before current fiscal year	4,820		4,820		7,361
Prior	18,351		18,351		13,199
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	30,318		30,318		33,161
Investor loans secured by real estate | SBA secured by real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		0
Fiscal Year before current fiscal year	0		0		0
Two Years before current fiscal year	0		0		0
Three Years before current fiscal year	0		0		0
Four Years before current fiscal year	534		534		2,416
Prior	8,024		8,024		6,558
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	8,558		8,558		8,974
Business loans secured by real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	19,190		19,190		676,516
Fiscal Year before current fiscal year	651,277		651,277		873,443
Two Years before current fiscal year	825,401		825,401		289,937
Three Years before current fiscal year	266,761		266,761		299,206
Four Years before current fiscal year	254,412		254,412		158,541
Prior	634,458		634,458		568,284
Revolving	5,845		5,845		5,661
Revolving Converted to Term During the Period	0		0		0
Total	2,657,344		2,657,344		2,871,588
Current fiscal year charge off			0
One year before current fiscal year charge off			0
Two year before current fiscal year charge off			318
Three year before current fiscal year charge off			191
Four year before current fiscal year charge off			0
Prior year before current fiscal year charge off			1,861
Revolving charge off			0
Revolving Converted to Term During the Period charge off			0
Total			2,370
Loans held for investment	2,657,344		2,657,344		2,871,588
Business loans secured by real estate | SBA secured by real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	57,084		57,084		61,368
Total	0	0	0	0
Loans held for investment	57,084		57,084		61,368
Business loans secured by real estate | SBA secured by real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	115		115		10,993
Fiscal Year before current fiscal year	9,951		9,951		6,978
Two Years before current fiscal year	8,079		8,079		2,329
Three Years before current fiscal year	2,128		2,128		5,710
Four Years before current fiscal year	5,140		5,140		4,440
Prior	26,014		26,014		25,415
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	51,427		51,427		55,865
Business loans secured by real estate | SBA secured by real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year					0
Fiscal Year before current fiscal year					0
Two Years before current fiscal year					0
Three Years before current fiscal year					0
Four Years before current fiscal year					0
Prior					118
Revolving					0
Revolving Converted to Term During the Period					0
Total					118
Business loans secured by real estate | SBA secured by real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		0
Fiscal Year before current fiscal year	0		0		0
Two Years before current fiscal year	0		0		0
Three Years before current fiscal year	0		0		0
Four Years before current fiscal year	0		0		1,354
Prior	5,657		5,657		4,031
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	5,657		5,657		5,385
Business loans secured by real estate | CRE owner-occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,281,721		2,281,721		2,432,163
Total	207	0	2,370	0
Loans held for investment	2,281,721		2,281,721		2,432,163
Business loans secured by real estate | CRE owner-occupied | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	11,456		11,456		593,826
Fiscal Year before current fiscal year	582,666		582,666		718,223
Two Years before current fiscal year	680,769		680,769		242,125
Three Years before current fiscal year	231,507		231,507		240,772
Four Years before current fiscal year	227,929		227,929		114,581
Prior	499,279		499,279		448,531
Revolving	5,845		5,845		5,661
Revolving Converted to Term During the Period	0		0		0
Total	2,239,451		2,239,451		2,363,719
Business loans secured by real estate | CRE owner-occupied | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		334
Fiscal Year before current fiscal year	0		0		1,015
Two Years before current fiscal year	2,816		2,816		0
Three Years before current fiscal year	0		0		0
Four Years before current fiscal year	0		0		675
Prior	15,229		15,229		327
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	18,045		18,045		2,351
Business loans secured by real estate | CRE owner-occupied | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		10,838
Fiscal Year before current fiscal year	10,348		10,348		2,541
Two Years before current fiscal year	0		0		11,970
Three Years before current fiscal year	4,251		4,251		2,403
Four Years before current fiscal year	0		0		4,676
Prior	9,626		9,626		33,665
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	24,225		24,225		66,093
Business loans secured by real estate | Franchise real estate secured
Financing Receivable, Credit Quality Indicator [Line Items]
Total	318,539		318,539		378,057
Total	0	0	0	0
Loans held for investment	318,539		318,539		378,057
Business loans secured by real estate | Franchise real estate secured | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	7,619		7,619		54,654
Fiscal Year before current fiscal year	39,661		39,661		131,541
Two Years before current fiscal year	129,858		129,858		33,513
Three Years before current fiscal year	28,875		28,875		44,229
Four Years before current fiscal year	16,617		16,617		32,815
Prior	78,356		78,356		55,893
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	300,986		300,986		352,645
Business loans secured by real estate | Franchise real estate secured | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		4,891
Fiscal Year before current fiscal year	7,701		7,701		13,145
Two Years before current fiscal year	3,879		3,879		0
Three Years before current fiscal year	0		0		0
Four Years before current fiscal year	823		823		0
Prior	0		0		0
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	12,403		12,403		18,036
Business loans secured by real estate | Franchise real estate secured | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		980
Fiscal Year before current fiscal year	950		950		0
Two Years before current fiscal year	0		0		0
Three Years before current fiscal year	0		0		6,092
Four Years before current fiscal year	3,903		3,903		0
Prior	297		297		304
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	5,150		5,150		7,376
Commercial loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	37,803		37,803		408,941
Fiscal Year before current fiscal year	335,980		335,980		408,923
Two Years before current fiscal year	338,774		338,774		78,071
Three Years before current fiscal year	71,283		71,283		221,057
Four Years before current fiscal year	174,511		174,511		112,268
Prior	237,671		237,671		170,512
Revolving	892,833		892,833		1,172,924
Revolving Converted to Term During the Period	17,540		17,540		4,143
Total	2,106,395		2,106,395		2,576,839
Current fiscal year charge off			0
One year before current fiscal year charge off			282
Two year before current fiscal year charge off			59
Three year before current fiscal year charge off			5
Four year before current fiscal year charge off			289
Prior year before current fiscal year charge off			36
Revolving charge off			677
Revolving Converted to Term During the Period charge off			0
Total			1,348
Loans held for investment	2,106,395		2,106,395		2,576,839
Commercial loans | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,744,763		1,744,763		2,160,948
Total	225	5,381	1,348	7,560
Loans held for investment	1,744,763		1,744,763		2,160,948
Commercial loans | Commercial and industrial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	29,948		29,948		282,131
Fiscal Year before current fiscal year	229,282		229,282		262,044
Two Years before current fiscal year	198,520		198,520		55,659
Three Years before current fiscal year	50,242		50,242		155,310
Four Years before current fiscal year	120,448		120,448		78,684
Prior	168,018		168,018		121,918
Revolving	856,579		856,579		1,134,568
Revolving Converted to Term During the Period	3,354		3,354		3,412
Total	1,656,391		1,656,391		2,093,726
Commercial loans | Commercial and industrial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		15,105
Fiscal Year before current fiscal year	5,152		5,152		3,567
Two Years before current fiscal year	12,709		12,709		798
Three Years before current fiscal year	0		0		0
Four Years before current fiscal year	561		561		1,864
Prior	0		0		41
Revolving	21,279		21,279		9,898
Revolving Converted to Term During the Period	55		55		0
Total	39,756		39,756		31,273
Commercial loans | Commercial and industrial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		2,590
Fiscal Year before current fiscal year	15,310		15,310		80
Two Years before current fiscal year	3,067		3,067		0
Three Years before current fiscal year	694		694		3,867
Four Years before current fiscal year	2		2		562
Prior	1,213		1,213		1,029
Revolving	14,199		14,199		27,680
Revolving Converted to Term During the Period	14,131		14,131		141
Total	48,616		48,616		35,949
Commercial loans | Franchise non-real estate secured
Financing Receivable, Credit Quality Indicator [Line Items]
Total	351,944		351,944		404,791
Total	0	448	0	448
Loans held for investment	351,944		351,944		404,791
Commercial loans | Franchise non-real estate secured | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	7,524		7,524		102,542
Fiscal Year before current fiscal year	79,358		79,358		128,030
Two Years before current fiscal year	122,005		122,005		18,486
Three Years before current fiscal year	17,431		17,431		46,027
Four Years before current fiscal year	39,975		39,975		28,664
Prior	63,563		63,563		43,486
Revolving	776		776		778
Revolving Converted to Term During the Period	0		0		0
Total	330,632		330,632		368,013
Commercial loans | Franchise non-real estate secured | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		1,372
Fiscal Year before current fiscal year	1,346		1,346		14,382
Two Years before current fiscal year	1,767		1,767		0
Three Years before current fiscal year	0		0		11,829
Four Years before current fiscal year	674		674		0
Prior	0		0		0
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	3,787		3,787		27,583
Commercial loans | Franchise non-real estate secured | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		1,757
Fiscal Year before current fiscal year	1,641		1,641		385
Two Years before current fiscal year	354		354		2,852
Three Years before current fiscal year	2,651		2,651		2,256
Four Years before current fiscal year	11,169		11,169		1,637
Prior	1,710		1,710		308
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	17,525		17,525		9,195
Commercial loans | SBA non-real estate secured
Financing Receivable, Credit Quality Indicator [Line Items]
Total	9,688		9,688		11,100
Total	0	0	0	50
Loans held for investment	9,688		9,688		11,100
Commercial loans | SBA non-real estate secured | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	331		331		3,444
Fiscal Year before current fiscal year	3,336		3,336		435
Two Years before current fiscal year	352		352		276
Three Years before current fiscal year	119		119		1,638
Four Years before current fiscal year	1,558		1,558		633
Prior	2,926		2,926		3,124
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	8,622		8,622		9,550
Commercial loans | SBA non-real estate secured | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		0
Fiscal Year before current fiscal year	555		555		0
Two Years before current fiscal year	0		0		0
Three Years before current fiscal year	146		146		130
Four Years before current fiscal year	124		124		224
Prior	241		241		606
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		590
Total	1,066		1,066		1,550
Retail loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	20		20		0
Fiscal Year before current fiscal year	0		0		6
Two Years before current fiscal year	3		3		193
Three Years before current fiscal year	185		185		11
Four Years before current fiscal year	8		8		22
Prior	46,374		46,374		50,730
Revolving	26,644		26,644		25,319
Revolving Converted to Term During the Period	0		0		0
Total	73,234		73,234		76,281
Current fiscal year charge off			0
One year before current fiscal year charge off			0
Two year before current fiscal year charge off			0
Three year before current fiscal year charge off			0
Four year before current fiscal year charge off			0
Prior year before current fiscal year charge off			983
Revolving charge off			2
Revolving Converted to Term During the Period charge off			0
Total			985
Loans held for investment	73,234		73,234		76,281
Retail loans | Single family residential
Financing Receivable, Credit Quality Indicator [Line Items]
Total	70,993		70,993		72,997
Total	0	0	90	0
Loans held for investment	70,993		70,993		72,997
Retail loans | Single family residential | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	20		20		0
Fiscal Year before current fiscal year	0		0		0
Two Years before current fiscal year	0		0		176
Three Years before current fiscal year	172		172		0
Four Years before current fiscal year	0		0		22
Prior	45,491		45,491		49,729
Revolving	25,308		25,308		23,065
Revolving Converted to Term During the Period	0		0		0
Total	70,991		70,991		72,992
Retail loans | Single family residential | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		0
Fiscal Year before current fiscal year	0		0		0
Two Years before current fiscal year	0		0		0
Three Years before current fiscal year	0		0		0
Four Years before current fiscal year	0		0		0
Prior	2		2		5
Revolving	0		0		0
Revolving Converted to Term During the Period	0		0		0
Total	2		2		5
Retail loans | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,241		2,241		3,284
Total	890	$ 2	895	$ 2
Loans held for investment	2,241		2,241		3,284
Retail loans | Consumer | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0		0		0
Fiscal Year before current fiscal year	0		0		6
Two Years before current fiscal year	3		3		17
Three Years before current fiscal year	13		13		11
Four Years before current fiscal year	8		8		0
Prior	881		881		969
Revolving	1,336		1,336		2,254
Revolving Converted to Term During the Period	0		0		0
Total	$ 2,241		$ 2,241		3,257
Retail loans | Consumer | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year					0
Fiscal Year before current fiscal year					0
Two Years before current fiscal year					0
Three Years before current fiscal year					0
Four Years before current fiscal year					0
Prior					27
Revolving					0
Revolving Converted to Term During the Period					0
Total					$ 27