Basis of Presentation and Signficant Accounting Policies Basis of Presentation and Significant Acconting Policies (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Approximate percentage of revenues subject to new revenue guidance under ASC 606		6.00%
Customer funds	$ 110.8	$ 110.8	$ 157.0
Adoption of new accounting pronouncement, tax benefit, amount	$ 2.1	$ 27.3
Adoption of new accounting pronouncement, tax benefit, amount per share	$ 0.01	$ 0.10

Effective income tax rate reconciliation, share-based compensation, excess tax benefit, per share, amount

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- Definition

Approximate percentage of revenues subject to new revenue guidance under ASC 606.

+ References

No definition available.

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- References

No definition available.

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- Definition

Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

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- Definition

The current cash, cash equivalents and investments that are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. Includes current cash equivalents and investments that are similarly restricted as to withdrawal, usage or disposal.

+ References

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 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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