Client Funds/Obligations (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended
Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Available-for-sale investments	Mar. 31, 2013 Available-for-sale investments
Client funds
Funds held on behalf of clients	$ 303.4	$ 316.3
Proceeds from the sales/maturities of investments, held to satisfy client funds obligations			$ 0	$ 29.7

The cash inflow associated with the sale and maturity (principal being due) of other investments, prepayment and call (request of early payment) of other investments not otherwise defined in the taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration