Revenue Recognition Disaggregation of Revenue (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										$ 934,822	$ 891,586
Interest										50,723	52,484	$ 48,498
Principal transactions, net										30,094	14,461	23,273
Revenues, Excluding Revenue From Contract With Customers, Other										17,740	(377)
Revenues, Excluding Revenue From Contract With Customers										98,557	66,568
Revenue		$ 295,881	$ 234,793	$ 250,935	$ 251,770	$ 243,254	$ 237,814	$ 242,556	$ 234,530	1,033,379	958,154	920,338
Commissions From Sales And Trading [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										280,069	286,211
Mutual Fund Income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										40,045	43,457
Advisory Fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										353,671	314,349
Investment Banking, Capital Markets [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										72,779	69,758
Investment Banking, Advisory [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										53,432	45,595
Investment Banking, Advisory [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										117,422	116,052
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										17,404	16,164
Private Client Division
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										597,763	584,236
Interest										35,809	37,581
Principal transactions, net										3,341	(1,125)
Revenues, Excluding Revenue From Contract With Customers, Other										16,496	(2,821)
Revenues, Excluding Revenue From Contract With Customers										55,646	33,635
Revenue	[1]									653,409	617,871	592,753
Private Client Division | Commissions From Sales And Trading [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										148,661	154,167
Private Client Division | Mutual Fund Income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										40,025	42,514
Private Client Division | Advisory Fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										264,839	243,474
Private Client Division | Investment Banking, Capital Markets [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										13,528	13,284
Private Client Division | Investment Banking, Advisory [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Private Client Division | Investment Banking, Advisory [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										117,422	116,052
Private Client Division | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										13,288	14,745
Asset Management
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										88,753	71,696
Interest										0	0
Principal transactions, net										0	0
Revenues, Excluding Revenue From Contract With Customers, Other										2	0
Revenues, Excluding Revenue From Contract With Customers										2	0
Revenue	[1]									88,755	71,696	89,896
Asset Management | Commissions From Sales And Trading [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Asset Management | Mutual Fund Income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	908
Asset Management | Advisory Fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										88,748	70,775
Asset Management | Investment Banking, Capital Markets [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Asset Management | Investment Banking, Advisory [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Asset Management | Investment Banking, Advisory [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Asset Management | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										5	13
Capital markets
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										245,789	235,158
Interest										13,302	13,739
Principal transactions, net										31,621	23,378
Revenues, Excluding Revenue From Contract With Customers, Other										118	444
Revenues, Excluding Revenue From Contract With Customers										45,041	37,561
Revenue										290,830	272,719	231,632
Capital markets | Commissions From Sales And Trading [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										131,380	131,955
Capital markets | Mutual Fund Income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										3	13
Capital markets | Advisory Fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										10	67
Capital markets | Investment Banking, Capital Markets [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										59,251	56,474
Capital markets | Investment Banking, Advisory [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										53,432	45,595
Capital markets | Investment Banking, Advisory [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Capital markets | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										1,713	1,054
Corporate/Other
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										2,517	496
Interest										1,612	1,164
Principal transactions, net										(4,868)	7,792
Revenues, Excluding Revenue From Contract With Customers, Other										1,124	2,000
Revenues, Excluding Revenue From Contract With Customers										(2,132)	(4,628)
Revenue										385	(4,132)	$ 6,057
Corporate/Other | Commissions From Sales And Trading [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										28	89
Corporate/Other | Mutual Fund Income [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										17	22
Corporate/Other | Advisory Fees [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										74	33
Corporate/Other | Investment Banking, Capital Markets [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Corporate/Other | Investment Banking, Advisory [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Corporate/Other | Investment Banking, Advisory [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Corporate/Other | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										$ 2,398	$ 352

[1] (1) Clients investing in the OAM advisory program are charged fees based on the value of AUM. Advisory fees were allocated 10.0% to the Asset Management and 90.0% to the Private Client segments.