Goodwill and Other Intangible Assets Gross and Net Carrying Amounts of Identifiable Intangible Assets (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross		$ 37,453	$ 73,553
Finite-Lived Intangible Assets, Accumulated Amortization		21,370	46,828
Finite-Lived Intangible Assets, Net		16,083	26,725
Advisory Contracts [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	[1]	37,313	71,513
Finite-Lived Intangible Assets, Accumulated Amortization	[1]	21,370	46,828
Finite-Lived Intangible Assets, Net	[1]	15,943	24,685
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	[1]	140	2,040
Finite-Lived Intangible Assets, Accumulated Amortization	[1]	0	0
Finite-Lived Intangible Assets, Net	[1]	$ 140	$ 2,040

[1] Intangible assets of Anchor are classified as held for sale as of December 31, 2017.