Goodwill and Intangible Assets - Finite-lived Intangible Assets Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Finite-lived Intangible Assets, Gross [Roll Forward]
Intangible assets, January 1			$ 35,240	$ 35,240	$ 35,240
Additions			0
Total intangible assets, end of year	$ 35,240		35,240		35,240
Accumulated Amortization [Roll Forward]
Accumulated amortization, January 1			(29,985)	(27,345)	(27,345)
Current year amortization	(519)	$ (662)	(1,552)	$ (1,980)	(2,640)
Total accumulated amortization	(31,537)		(31,537)		(29,985)
Net intangible assets
Net intangible assets, end of year	3,703		3,703		5,255
Infinite-lived intangible assets	6,892		6,892		6,892
Total net intangible assets	$ 10,595		$ 10,595		$ 12,147