Bank Call Loans - Summary of Bank Call Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Bank Call Loans [Abstract]
Year-end balance	$ 0	$ 15,000
Weighted interest rate (at end of year)	0.00%	3.43%
Maximum balance (at any month-end)	$ 76,900	$ 161,800
Bank Call Loans Average Amount Outstanding	$ 11,063	$ 53,271
Average interest rate (during the year)	3.27%	2.66%