Stockholders' Deficit - Share Repurchases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Class of Stock [Line Items]
Stock repurchased during period, value	$ 4,480	$ 26,527	$ 111,697
2019 Repurchase Program
Class of Stock [Line Items]
Stock repurchased during period (in shares)	59,099	459,899	1,237,698
Stock repurchased during period, value	$ 4,500	$ 26,500	$ 103,300
Cumulative amount of shares repurchased (in shares)	1,756,696
Cumulative payments for repurchase of common stock	$ 134,300
Remaining dollar value of shares that may be repurchased	$ 65,700
2015 Repurchase Program
Class of Stock [Line Items]
Stock repurchased during period (in shares)			110,499
Stock repurchased during period, value			$ 8,400
Cumulative amount of shares repurchased (in shares)		1,589,995
Cumulative payments for repurchase of common stock		$ 126,200