Information about Geographic Areas and Products - Subscription Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenues	$ 2,608,816	$ 1,918,494	[1]	$ 1,390,985	[1]
Service management products
Segment Reporting Information [Line Items]
Revenues	2,050,841	1,526,125		1,120,129
ITOM products
Segment Reporting Information [Line Items]
Revenues	370,472	213,375		113,941
Total subscription revenues
Segment Reporting Information [Line Items]
Revenues	$ 2,421,313	$ 1,739,500	[1]	$ 1,234,070	[1]

[1] As adjusted to reflect the impact of the full retrospective adoption of Topic 606.