Income Taxes - Unrecognized Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Unrecognized Tax Benefit Activity [Roll Forward]
Beginning balance	$ 5,315	$ 3,954	$ 1,686
Additions based on tax positions related to the current year	0	1,087	2,268
Increases (decreases) for tax positions of prior years	2,416	274	0
Statute of limitations expiration	(1,266)	0	0
Ending balance	$ 6,465	$ 5,315	$ 3,954