Fair Value Measurements and Risk - Carrying Amounts and Fair Values of Debt (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	$ 1,983.0	$ 1,983.3
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other borrowings	54.3	51.6
Total debt	1,983.0	1,983.3
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other borrowings	54.3	51.6
Total debt	2,032.2	1,965.7
2025 Term Loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	934.8	938.9
Unamortized discount and debt issuance costs	8.1	8.7
2025 Term Loan \| Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	934.8	938.9
2025 Term Loan \| Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	932.5	914.8
5.125% Senior Notes, Due 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	$ 696.6	$ 695.8
Interest rate (percent)	5.125%	5.125%
Unamortized discount and debt issuance costs	$ 3.4	$ 4.2
5.125% Senior Notes, Due 2021 \| Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	696.6	695.8
5.125% Senior Notes, Due 2021 \| Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	723.6	697.5
5.625% Senior Notes, Due 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	$ 297.3	$ 297.0
Interest rate (percent)	5.625%	5.625%
Unamortized discount and debt issuance costs	$ 2.7	$ 3.0
5.625% Senior Notes, Due 2024 \| Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	297.3	297.0
5.625% Senior Notes, Due 2024 \| Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt	$ 321.8	$ 301.8

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399

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Represents the aggregate of total long-term debt, including current maturities and short-term debt.

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The carrying amount as of the balance sheet date for the aggregate of other miscellaneous borrowings owed by the reporting entity.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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