Bank Call Loans - Summary of Bank Call Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Bank Call Loans [Abstract]
Year-end balance	$ 82,000	$ 0
Weighted interest rate (at end of year)	1.09%	0.00%
Maximum balance (at any month-end)	$ 203,100	$ 76,900
Bank Call Loans Average Amount Outstanding	$ 82,760	$ 11,063
Average interest rate (during the year)	0.93%	3.27%