Stockholders' Equity - CEO Performance Award (Details) $ in Thousands		12 Months Ended			48 Months Ended
	May 24, 2018 tranche shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 shares	Dec. 31, 2016 shares	Dec. 31, 2011 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
New option granted (in shares) | shares		0	0	0
First tranche		$ 2,500,000
Incremental increase		1,000,000
Incremental stock option expense		$ 3,300
Number of Options expected to vest, end of year (in shares) | shares		1,100,000
Weighted average period		7 years 2 months 12 days
Revenue Goal 1		$ 710,058
Adjusted EBITDA Goal 9		125,000
Revenue Goal 2		860,058
Adjusted EBITDA Goal 10		155,000
Revenue Goal 3		1,010,058
Adjusted EBITDA Goal 11		175,000
Revenue Goal 4		1,210,058
Adjusted EBITDA Goal 12		190,000
Revenue Goal 5		1,410,058
Adjusted EBITDA Goal 13		200,000
Revenue Goal 6		1,610,058
Adjusted EBITDA Goal 14		210,000
Revenue Goal 7		1,810,058
Adjusted EBITDA Goal 15		220,000
Revenue Goal 8		2,010,058
Adjusted EBITDA Goal 16		230,000
Total revenue		710,100
Adjusted EBITDA		125,000
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
New option granted (in shares) | shares	6,365,856				1,000,000
Total unrecognized stock-based compensation expense for operational goals		42,000
Unrecognized expense for the operational goals that were not probable of achievement		$ 200,700
Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of vesting tranches of share-based awards | tranche	12