Accounting Policies and Basis of Presentation Accounting Policies and Basis of Presentation (Recently Adopted Accounting Standards) (Details) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2021 shares	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2021 USD ($) loan	Sep. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2020 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock repurchased during period (in USD per share) | $ / shares		$ 399.82
SBA-PPP Loan			$ 32,516,189		$ 32,791,975
SBA-PPP
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of loans originated | loan			12,000
Loans receivable, period increase			$ 1,200,000
SBA-PPP Loan			$ 1,100,000
Class A Common Stock
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock repurchased during period (in shares) | shares		117,700		813,090
Stock repurchased during period		$ 47,060		$ 333,755
Stock repurchased during period (in USD per share) | $ / shares				$ 410.48
Class A Common Stock | Repurchases From Ella Ann Holding
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock repurchased during period (in shares) | shares	45,000