Deferred Revenue and Performance Obligations - Summary of Deferred Revenue Balances (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
Deferred Revenue Arrangement [Line Items]
Deferred revenue balance, beginning of period	$ 119,301
Revenue recognized during the period	(53,486)
Additions to deferred revenue during the period, including deferred revenue acquired	57,629
Deferred revenue balance, end of period	123,444
Subscription
Deferred Revenue Arrangement [Line Items]
Deferred revenue balance, beginning of period	110,934
Revenue recognized during the period	(45,471)
Additions to deferred revenue during the period, including deferred revenue acquired	48,407
Deferred revenue balance, end of period	113,870
Services
Deferred Revenue Arrangement [Line Items]
Deferred revenue balance, beginning of period	8,367
Revenue recognized during the period	(8,015)
Additions to deferred revenue during the period, including deferred revenue acquired	9,222
Deferred revenue balance, end of period	$ 9,574