Business Combinations - Supplemental Cash Flow Disclosures (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2020
Business Combinations [Abstract]
Fair value of tangible assets acquired		$ 21,484,601
Goodwill, loan servicing rights and other identifiable intangible assets acquired		1,377,388
Liabilities assumed		19,843,433
Common stock and stock options converted		$ 3,018,556
Adjustments to fair value, decrease in loans and leases	$ (17,200)
Adjustments to fair value, increase in deferred tax asset	4,000
Adjustments to fair value, increase in goodwill	$ 13,200