New Accounting Pronouncement - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended
	Jan. 02, 2020	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Debt securities held to maturity allowance for credit loss		$ 13,390	$ 0
Recorded investment current		25,580,783	25,603,271
Stockholders equity		5,669,605	6,016,779	$ 5,440,060	$ 5,435,057
Cumulative effect adoption adjustment
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Stockholders equity			$ (205,842)		$ 4,905
Unfunded loan commitment
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Allowance for credit loss, increase (decrease)	$ (9,000)
Loan portfolio
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Allowance for credit loss, increase (decrease)	315,000
ASU 2016-13
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Accruing loans past-due 90 days or more	144,000
Non-accrual loans	278,000
Recorded investment current	134,000
ASC Subtopic 310-30
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Allowance for credit loss, increase (decrease)		$ 17,000
Accruing loans past-due 90 days or more	144,000
Recorded investment current	$ 134,000