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	6 Months Ended		12 Months Ended
	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2021 USD ($) loan	Jun. 30, 2020 USD ($) $ / shares shares	Dec. 31, 2020 shares
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock repurchased during period (in USD per share) | $ / shares	$ 367.03
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
Loans and leases, not acquired in a transfer accounted for as debt securities		$ 1,700,000
Class A Common Stock
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stock repurchased during period (in shares) | shares	346,000		695,390
Stock repurchased during period	$ 126,991		$ 286,695
Stock repurchased during period (in USD per share) | $ / shares			$ 412.28
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