Convertible Senior Notes - Schedule of Note Hedges (Details) - USD ($) shares in Thousands, $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Nov. 30, 2013	Jun. 30, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Purchase			$ 0	$ 0	$ 128,017
2022 Note Hedge
Debt Instrument [Line Items]
Purchase			$ 128,017
Shares (in shares)		5,807
Shares as of December 31, 2019 (in shares)			5,807
2018 Note Hedge
Debt Instrument [Line Items]
Purchase			$ 135,815
Shares (in shares)	7,783
Shares as of December 31, 2019 (in shares)			0