Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13433-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13476-108611

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

Fair Value Measurements - Debt (Details) - Estimate of Fair Value Measurement - Fair Value, Inputs, Level 2 - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
2023 Senior Notes
Debt
Fair value of debt	$ 437.5
2.5 Percent Convertible Notes
Debt
Fair value of debt	246.0	$ 332.0
2015 Term Loan Facility
Debt
Fair value of debt	$ 337.8
2014 Term Loan Facility
Debt
Fair value of debt		$ 342.0