Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended
Apr. 11, 2014 Healthcare Strategies, Inc., Plan [Member]	Sep. 26, 2012 Healthcare Strategies, Inc., Plan [Member] plantiff	Sep. 30, 2014 Investment purchase commitment	Dec. 31, 2013 Investment purchase commitment
Loss Contingencies [Line Items]
Off-balance sheet commitment to purchase investments			$ 472.1	$ 466.8
Number of plaintiffs		15,000
Damages sought by plaintiffs	$ 15.0

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 9

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

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