Segment Information (Details)	12 Months Ended
Dec. 31, 2015 segment channel	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting [Abstract]
Number of operating segments \| segment	3
Number of principal distribution channels \| channel	3
Revenue attributable to clients domiciled outside the United States (as a percent)	40.00%	37.00%	38.00%

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

No definition available.

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration