Acquisitions, Divestiture, Intangible Assets and Goodwill (Divestiture) (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
May 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Proceeds from sale of businesses, net of cash transferred	$ 292,000	$ 0	$ 0	$ 289,211
Gain on sale of businesses	$ 111,000	$ 0	$ (5,786)	$ 105,826

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

Name:	us-gaap_ProceedsFromDivestitureOfBusinesses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration