Revenue from Contracts with Customers (Contract Liability) (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2019	Jan. 01, 2019
Revenue from Contract with Customer [Abstract]
Deferred Revenue	$ 245,729	$ 311,214
Deferred Revenue, Period Decrease Percentage	(21.00%)

Amount of deferred income and obligation to transfer product and service to customer for which consideration has been received or is receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(5))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_DeferredRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant