Fair Value Measurements - Long-term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Long-term debt, Carrying value	$ 435.8	$ 148.0
Long-term debt, Estimated fair value	426.5	148.1
Senior Loans [Member]
Debt Instrument [Line Items]
Long-term debt, Carrying value	387.2	132.0
Senior Loans [Member] \| Level 3 [Member]
Debt Instrument [Line Items]
Long-term debt, Estimated fair value	377.8	132.0
Junior Loans [Member]
Debt Instrument [Line Items]
Long-term debt, Carrying value	48.6	16.0
Junior Loans [Member] \| Level 3 [Member]
Debt Instrument [Line Items]
Long-term debt, Estimated fair value	$ 48.7	$ 16.1

Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

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