Loans, Allowance for Loan Losses and Allowance for Unfunded Credit Commitments - Composition of Loans, Net of Unearned Income (Additional Information) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 33,164,636	$ 28,338,280
Credit card receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	395,000	335,000
Real estate secured loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	4,146,347	3,363,803
Real estate secured loans | Construction loans, premium wine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	83,000	99,000
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	3,776,686	3,033,643
Consumer loans | Real estate secured loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	3,286,737	2,612,971
Consumer loans | Real estate secured loans | Loans for personal residence
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	2,829,880	2,251,292
Consumer loans | Real estate secured loans | Loans to eligible employees
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	401,396	290,194
Consumer loans | Real estate secured loans | Home equity lines of credit
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 55,461	$ 71,485