Segment Information (Subscription Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Total Subscription revenue	$ 732,901	$ 732,476	$ 2,200,741	$ 2,172,033
Subscription [Member]
Segment Reporting Information [Line Items]
Total Subscription revenue	159,873	111,539	457,312	325,493
Subscription, SaaS [Member]
Segment Reporting Information [Line Items]
Total Subscription revenue	100,857	70,768	277,512	195,527
Subscription, Non-SaaS [Member]
Segment Reporting Information [Line Items]
Total Subscription revenue	$ 59,016	$ 40,771	$ 179,800	$ 129,966

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration