Loans and Leases - Credit Risk Rating Categories for Loans and Leases Held for Investment (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	$ 25,672,381	$ 28,609,129	$ 24,352,072
Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	15,407,611	15,730,324	12,509,064
Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	4,608,440	4,152,172	3,223,716
Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	5,229,107	8,281,962	8,114,695
Consumer
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	427,223	444,671	$ 504,597
Classified
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	132,423	118,271
Classified | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	115,564	107,905
Classified | Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	0	0
Classified | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	16,161	10,091
Classified | Consumer
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	698	275
Special Mention
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	580,153	566,259
Special Mention | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	269,922	224,886
Special Mention | Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	138,638	136,489
Special Mention | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	164,591	197,976
Special Mention | Consumer
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	7,002	6,908
Pass
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	24,959,805	27,924,599
Pass | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	15,022,125	15,397,533
Pass | Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	4,469,802	4,015,683
Pass | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	5,048,355	8,073,895
Pass | Consumer
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	419,523	437,488
Asset-based | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	2,068,327	5,140,209
Asset-based | Classified | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	420	865
Asset-based | Special Mention | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	33,133	56,836
Asset-based | Pass | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	2,034,774	5,082,508
Venture Capital Loans | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	2,058,237	2,033,302
Venture Capital Loans | Classified | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	2,615	2,753
Venture Capital Loans | Special Mention | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	126,422	127,907
Venture Capital Loans | Pass | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	1,929,200	1,902,642
Other Commercial | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	1,102,543	1,108,451
Other Commercial | Classified | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	13,126	6,473
Other Commercial | Special Mention | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	5,036	13,233
Other Commercial | Pass | Commercial
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	1,084,381	1,088,745
Commercial Real Estate Construction Loan Receivable | Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	910,327	898,592
Commercial Real Estate Construction Loan Receivable | Classified | Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	0	0
Commercial Real Estate Construction Loan Receivable | Special Mention | Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	93,641	91,334
Commercial Real Estate Construction Loan Receivable | Pass | Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	816,686	807,258
Residential Real Estate Construction Financing Receivable | Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	3,698,113	3,253,580
Residential Real Estate Construction Financing Receivable | Classified | Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	0	0
Residential Real Estate Construction Financing Receivable | Special Mention | Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	44,997	45,155
Residential Real Estate Construction Financing Receivable | Pass | Real Estate Construction and Land
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	3,653,116	3,208,425
Commercial | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	3,808,751	3,846,831
Commercial | Classified | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	35,596	43,737
Commercial | Special Mention | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	109,020	106,493
Commercial | Pass | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	3,664,135	3,696,601
Multi-Family Real Estate Loans | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	5,523,320	5,607,865
Multi-Family Real Estate Loans | Classified | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	3,586	3,611
Multi-Family Real Estate Loans | Special Mention | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	116,092	60,330
Multi-Family Real Estate Loans | Pass | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	5,403,642	5,543,924
Other Residential Real Estate | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	6,075,540	6,275,628
Other Residential Real Estate | Classified | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	76,382	60,557
Other Residential Real Estate | Special Mention | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	44,810	58,063
Other Residential Real Estate | Pass | Real Estate Mortgage
Financing Receivable, Past Due [Line Items]
Loans held for investment, net	$ 5,954,348	6,157,008
Non Purchased Credit Impaired Loans and Leases
Financing Receivable, Past Due [Line Items]
Loans held for investment, net		$ 28,609,129