Intangible Assets - Finite-lived Intangible Assets Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Finite-lived Intangible Assets, Gross [Roll Forward]
Intangible assets, beginning of period	$ 35,240	$ 35,240
Additions	0
Total intangible assets, end of period	35,240	35,240	$ 35,240
Accumulated Amortization [Roll Forward]
Accumulated amortization, January 1	(32,055)	(29,985)
Current year amortization	(1,521)	(2,070)	(2,640)
Total accumulated amortization	(33,576)	(32,055)	$ (29,985)
Net intangible assets
Net intangible assets, end of year	1,664	3,185
Infinite-lived intangible assets	6,892	6,892
Total net intangible assets	$ 8,556	$ 10,077