Current Accounting Developments and Summary of Significant Accounting Policies (Details) $ in Thousands	1 Months Ended	6 Months Ended
	Apr. 30, 2020	Jun. 30, 2020 USD ($) loan	Jan. 01, 2020 USD ($)	Dec. 31, 2019 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan losses		$ 632,071		$ 358,287
Retained earnings		3,755,649		$ 3,689,377
Commercial and industrial (“C&I”)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan losses		$ 756
Commercial and industrial (“C&I”) | CARES Act, Paycheck Protection Program
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest rate	1.00%
Number of loans funded | loan		7,200
Outstanding loan balance		$ 1,750,000
Term of loan		2 years
ASU 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan losses			$ 125,200
Retained earnings			98,000
ASU 2016-13 | Unfunded Credit Commitments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan losses			$ 10,500