Loans, Leases and Allowance for Credit Losses - Contractual Aging of Loan Portfolio by Class of Loans Including Loans Held for Sale and Excluding Deferred Fees/Costs (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) SecurityLoan	Jun. 30, 2019 SecurityLoan	Jun. 30, 2020 USD ($) SecurityLoan	Jun. 30, 2019 USD ($) SecurityLoan	Dec. 31, 2019 USD ($)
Financing Receivable, Past Due [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification	$ 10,800		$ 36,743
Financing Receivable, Modifications, Number of Contracts | SecurityLoan	2	2	8	4
Financing Receivable, Troubled Debt Restructuring, Subsequent Default				$ 400
Financing Receivable, Not Past Due	$ 24,967,011		$ 24,967,011		$ 21,065,187
Financing Receivable, Past Due	42,204		42,204		36,306
Loans and Leases Receivable, Net of Deferred Income	25,009,215		25,009,215		21,101,493
Financing Receivable, Nonaccrual	119,508		119,508		55,968
Financing Receivable, 90 Days or More Past Due, Still Accruing	0		0		0
Commercial and industrial [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due					9,376,377
Financing Receivable, Past Due					5,666
Loans and Leases Receivable, Net of Deferred Income					9,382,043
Financing Receivable, Nonaccrual					24,501
Financing Receivable, 90 Days or More Past Due, Still Accruing					0
Residential Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due					2,134,346
Financing Receivable, Past Due					13,318
Loans and Leases Receivable, Net of Deferred Income					2,147,664
Financing Receivable, 90 Days or More Past Due, Still Accruing					0
Consumer Loan [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due					57,083
Financing Receivable, Past Due					0
Loans and Leases Receivable, Net of Deferred Income					57,083
Financing Receivable, 90 Days or More Past Due, Still Accruing					0
Non-accrual loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due					34,141
Financing Receivable, Past Due					21,827
Non-accrual loans [Member] | Commercial and industrial [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due					19,080
Financing Receivable, Past Due					5,421
Non-accrual loans [Member] | Residential Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due					1,231
Financing Receivable, Past Due					4,369
Financing Receivable, Nonaccrual					5,600
Non-accrual loans [Member] | Consumer Loan [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due					0
Financing Receivable, Past Due					0
Financing Receivable, Nonaccrual					0
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	9,184		9,184		15,413
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial and industrial [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					2,501
Financial Asset, 30 to 59 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					7,627
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Loan [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					0
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	7,445		7,445		2,358
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial and industrial [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					637
Financial Asset, 60 to 89 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					1,721
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Loan [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	25,575		25,575		18,535
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial and industrial [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					2,528
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					3,970
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Loan [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					0
Commercial and industrial [Member]
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income					9,382,043
Tech & Innovation [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification			$ 9,968
Financing Receivable, Modifications, Number of Contracts | SecurityLoan			1
Financing Receivable, Not Past Due	2,123,722		$ 2,123,722
Financing Receivable, Past Due	0		0
Loans and Leases Receivable, Net of Deferred Income	2,123,722		2,123,722
Financing Receivable, Nonaccrual	48,968		48,968
Financing Receivable, 90 Days or More Past Due, Still Accruing	0		0
Tech & Innovation [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Tech & Innovation [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Tech & Innovation [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Other commercial and industrial [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification			$ 20,211
Financing Receivable, Modifications, Number of Contracts | SecurityLoan			3
Financing Receivable, Not Past Due	6,245,408		$ 6,245,408
Financing Receivable, Past Due	1,861		1,861
Loans and Leases Receivable, Net of Deferred Income	6,247,269		6,247,269
Financing Receivable, Nonaccrual	11,877		11,877
Financing Receivable, 90 Days or More Past Due, Still Accruing	0		0
Other commercial and industrial [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,170		1,170
Other commercial and industrial [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	467		467
Other commercial and industrial [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	224		224
Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification			$ 2,261
Financing Receivable, Modifications, Number of Contracts | SecurityLoan			3
Financing Receivable, Not Past Due	2,002,781		$ 2,002,781
Financing Receivable, Past Due	8,540		8,540
Loans and Leases Receivable, Net of Deferred Income	2,011,321		2,011,321		2,316,913
Financing Receivable, Nonaccrual	23,185		23,185
Financing Receivable, 90 Days or More Past Due, Still Accruing	0		0
Commercial Real Estate Owner Occupied [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due					2,316,165
Financing Receivable, Past Due					748
Loans and Leases Receivable, Net of Deferred Income					2,316,913
Financing Receivable, 90 Days or More Past Due, Still Accruing					0
Commercial Real Estate Owner Occupied [Member] | Non-accrual loans [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due					4,418
Financing Receivable, Past Due					124
Financing Receivable, Nonaccrual					4,542
Commercial Real Estate Owner Occupied [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	273		273
Commercial Real Estate Owner Occupied [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					624
Commercial Real Estate Owner Occupied [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,699		1,699
Commercial Real Estate Owner Occupied [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					0
Commercial Real Estate Owner Occupied [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	6,568		6,568
Commercial Real Estate Owner Occupied [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					124
Commercial Real Estate Non Owner Occupied [Member]
Financing Receivable, Past Due [Line Items]
Loans and Leases Receivable, Net of Deferred Income					5,245,634
Commercial Real Estate Non Owner Occupied [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due					5,007,644
Financing Receivable, Past Due					16,574
Loans and Leases Receivable, Net of Deferred Income					5,024,218
Financing Receivable, 90 Days or More Past Due, Still Accruing					0
Commercial Real Estate Non Owner Occupied [Member] | Non-accrual loans [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due					7,265
Financing Receivable, Past Due					11,913
Financing Receivable, Nonaccrual					19,178
Commercial Real Estate Non Owner Occupied [Member] | Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					4,661
Commercial Real Estate Non Owner Occupied [Member] | Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					0
Commercial Real Estate Non Owner Occupied [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due					11,913
Hotel franchise finance [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification			$ 0
Financing Receivable, Modifications, Number of Contracts | SecurityLoan			0
Financing Receivable, Not Past Due	1,876,980		$ 1,876,980
Financing Receivable, Past Due	0		0
Loans and Leases Receivable, Net of Deferred Income	1,876,980		1,876,980
Financing Receivable, Nonaccrual	0		0
Financing Receivable, 90 Days or More Past Due, Still Accruing	0		0
Hotel franchise finance [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Hotel franchise finance [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Hotel franchise finance [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Other Commercial Real Estate Non owner Occupied [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Troubled Debt Restructuring, Postmodification			$ 4,304
Financing Receivable, Modifications, Number of Contracts | SecurityLoan			1
Financing Receivable, Not Past Due	3,412,562		$ 3,412,562
Financing Receivable, Past Due	22,298		22,298
Loans and Leases Receivable, Net of Deferred Income	3,434,860		3,434,860
Financing Receivable, Nonaccrual	28,791		28,791
Financing Receivable, 90 Days or More Past Due, Still Accruing	0		0
Other Commercial Real Estate Non owner Occupied [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,997		1,997
Other Commercial Real Estate Non owner Occupied [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	3,959		3,959
Other Commercial Real Estate Non owner Occupied [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	16,342		16,342
Construction And Land Development [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due	2,168,310		2,168,310
Financing Receivable, Past Due	0		0
Loans and Leases Receivable, Net of Deferred Income	2,168,310		2,168,310		1,952,156
Financing Receivable, Nonaccrual	0		0
Financing Receivable, 90 Days or More Past Due, Still Accruing	0		0
Construction And Land Development [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Construction And Land Development [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Construction And Land Development [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Warehouse lending [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due	2,898,736		2,898,736
Financing Receivable, Past Due	0		0
Loans and Leases Receivable, Net of Deferred Income	2,898,736		2,898,736
Financing Receivable, Nonaccrual	0		0
Financing Receivable, 90 Days or More Past Due, Still Accruing	0		0
Warehouse lending [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Warehouse lending [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Warehouse lending [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Municipal and nonprofit [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due	1,685,481		1,685,481
Financing Receivable, Past Due	0		0
Loans and Leases Receivable, Net of Deferred Income	1,685,481		1,685,481
Financing Receivable, Nonaccrual	2,017		2,017
Financing Receivable, 90 Days or More Past Due, Still Accruing	0		0
Municipal and nonprofit [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Municipal and nonprofit [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Municipal and nonprofit [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0		0
Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due	212,926		212,926
Financing Receivable, Past Due	251		251
Loans and Leases Receivable, Net of Deferred Income	213,177		213,177
Financing Receivable, Nonaccrual	231		231
Financing Receivable, 90 Days or More Past Due, Still Accruing	0		0
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	17		17
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	10		10
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	224		224
Residential Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Not Past Due	2,340,105		2,340,105
Financing Receivable, Past Due	9,254		9,254
Loans and Leases Receivable, Net of Deferred Income	2,349,359		2,349,359		$ 2,147,664
Financing Receivable, Nonaccrual	4,439		4,439
Financing Receivable, 90 Days or More Past Due, Still Accruing	0		0
Residential Real Estate [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	5,727		5,727
Residential Real Estate [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,310		1,310
Residential Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 2,217		$ 2,217