Goodwill and Intangibles Schedule of Goodwill by Segment (Details) (Annual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Goodwill, Gross	$ 80,363	$ 80,363	$ 78,046
Goodwill	60,678	58,361
Goodwill, Acquired During Period	0	3,519
Goodwill, Other Changes	0	(1,202)
Goodwill impairment	0	0
Goodwill, Impaired, Accumulated Impairment Loss	19,685	19,685	19,685
Goodwill	60,678	60,678
Investment Management
Goodwill [Roll Forward]
Goodwill, Gross	29,026	29,026	30,228
Goodwill	18,826	20,028
Goodwill, Acquired During Period	0	0
Goodwill, Other Changes	0	(1,202)
Goodwill impairment	0	0
Goodwill, Impaired, Accumulated Impairment Loss	10,200	10,200	10,200
Goodwill	18,826	18,826
Broker-Dealer
Goodwill [Roll Forward]
Goodwill, Gross	51,337	51,337	47,818
Goodwill	41,852	38,333
Goodwill, Acquired During Period	0	3,519
Goodwill, Other Changes	0	0
Goodwill impairment	0	0
Goodwill, Impaired, Accumulated Impairment Loss	9,485	9,485	$ 9,485
Goodwill	$ 41,852	41,852
CRT business | Broker-Dealer
Goodwill [Roll Forward]
Goodwill, Acquired During Period		3,500
Finite-lived Intangible Assets Acquired		$ 5,100
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		8 years 1 month 6 days
Alternative Solutions [Member] | Investment Management
Goodwill [Roll Forward]
Goodwill, Other Changes		$ 1,200