Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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

Subsidiary Guarantors - Debt and Equity (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Feb. 23, 2015	Apr. 01, 2014
Senior notes \| 2022 Notes
Subsidiary Guarantors
Issuance of debt			$ 500.0
Senior notes \| 2023 Notes
Subsidiary Guarantors
Issuance of debt		$ 250.0
Issuers \| Guarantor Subsidiaries
Subsidiary Guarantors
Ownership percentage in subsidiary guarantors	100.00%