Other Assets - Investments - Equity Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity Securities
Investments - equity securities	$ 450	$ 2,623
Unrealized gain (loss) on investments held as of balance sheet date	(900)	(4,600)	$ (6,300)
Preferred stock
Equity Securities
Investments - equity securities	$ 500	$ 2,600