New Accounting Pronouncements - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Allowance for credit losses	$ 200,563	$ 215,973
Reduction to retained earnings, net of deferred tax balances	(2,040,134)	$ (1,891,246)
ASU Nos. 2016-13 [Member] | Cumulative Effect Adjustments [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Allowance for credit losses	9,000
Reduction to retained earnings, net of deferred tax balances	$ 7,000