Stockholders' Deficit - Share Repurchases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock [Line Items]
Stock repurchased during period, value	$ 111,697	$ 34,929	$ 10,003
2019 Repurchase Program
Class of Stock [Line Items]
Stock repurchased during period (in shares)	1,237,698
Stock repurchased during period, value	$ 103,300
Remaining dollar value of shares that may be repurchased	$ 96,700
October 2015 Share 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