Acquisitions (Identifiable Intangible Assets) (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 02, 2015	Dec. 31, 2017
Acquired Indefinite-lived Intangible Assets [Line Items]
Estimated Useful Life		8 years 9 months 27 days
Technology
Acquired Indefinite-lived Intangible Assets [Line Items]
Estimated Useful Life		7 years 9 months 60 days
Trade names
Acquired Indefinite-lived Intangible Assets [Line Items]
Estimated Useful Life		7 years 8 months 12 days
SSN
Acquired Indefinite-lived Intangible Assets [Line Items]
Identifiable intangible assets	$ 30,901
SSN \| Relationships with financial advisors
Acquired Indefinite-lived Intangible Assets [Line Items]
Identifiable intangible assets	$ 26,654
Estimated Useful Life	20 years
SSN \| Technology
Acquired Indefinite-lived Intangible Assets [Line Items]
Identifiable intangible assets	$ 2,080
Estimated Useful Life	12 years 6 months
SSN \| Trade names
Acquired Indefinite-lived Intangible Assets [Line Items]
Identifiable intangible assets	$ 1,756
Estimated Useful Life	9 years
SSN \| Non-compete agreements
Acquired Indefinite-lived Intangible Assets [Line Items]
Identifiable intangible assets	$ 411
Estimated Useful Life	3 years