Revenue Recognition Contract Assets and Liabilities (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	Jan. 01, 2018
Contracts with Customers Assets and Liabilities [Line Items]
Capitalized Contract Cost, Gross		$ 1,400				$ 1,600				$ 1,400	$ 1,600
Revenue from Contract with Customer, Excluding Assessed Tax										934,822	891,586
Contract with Customer, Asset, after Allowance for Credit Loss		28,888								28,888			$ 23,680
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
Commission [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Contract with Customer, Asset, after Allowance for Credit Loss		2,824								2,824			3,738
Mutual Fund Income [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Contract with Customer, Asset, after Allowance for Credit Loss		6,746								6,746			7,241
Advisory Fees [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Contract with Customer, Asset, after Allowance for Credit Loss		1,594								1,594			1,214
Bank Deposit Sweep Income [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Contract with Customer, Asset, after Allowance for Credit Loss		3,454								3,454			4,622
Investment Banking Fees [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Contract with Customer, Asset, after Allowance for Credit Loss		9,284								9,284			3,996
Other
Contracts with Customers Assets and Liabilities [Line Items]
Contract with Customer, Asset, after Allowance for Credit Loss		4,986								4,986			2,869
Investment Banking Fees [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Contract with Customer, Liability		$ 408								408			$ 318
Asset Management
Contracts with Customers Assets and Liabilities [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
Capital markets
Contracts with Customers Assets and Liabilities [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
Corporate/Other
Contracts with Customers Assets and Liabilities [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
Private Client Division
Contracts with Customers Assets and Liabilities [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
Other [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										17,404	16,164
Other [Member] | Asset Management
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										5	13
Other [Member] | Capital markets
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										1,713	1,054
Other [Member] | Corporate/Other
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										2,398	352
Other [Member] | Private Client Division
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										13,288	14,745
Investment Banking, Capital Markets [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										72,779	69,758
Investment Banking, Capital Markets [Member] | Asset Management
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Investment Banking, Capital Markets [Member] | Capital markets
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										59,251	56,474
Investment Banking, Capital Markets [Member] | Corporate/Other
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Investment Banking, Capital Markets [Member] | Private Client Division
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										13,528	13,284
Advisory Fees [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										353,671	314,349
Advisory Fees [Member] | Asset Management
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										88,748	70,775
Advisory Fees [Member] | Capital markets
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										10	67
Advisory Fees [Member] | Corporate/Other
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										74	33
Advisory Fees [Member] | Private Client Division
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										264,839	243,474
Mutual Fund Income [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										40,045	43,457
Mutual Fund Income [Member] | Asset Management
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	908
Mutual Fund Income [Member] | Capital markets
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										3	13
Mutual Fund Income [Member] | Corporate/Other
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										17	22
Mutual Fund Income [Member] | Private Client Division
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										40,025	42,514
Investment Banking, Advisory [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										53,432	45,595
Investment Banking, Advisory [Member] | Asset Management
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Investment Banking, Advisory [Member] | Capital markets
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										53,432	45,595
Investment Banking, Advisory [Member] | Corporate/Other
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Investment Banking, Advisory [Member] | Private Client Division
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Bank Deposit Sweep Income [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										117,422	116,052
Bank Deposit Sweep Income [Member] | Asset Management
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Bank Deposit Sweep Income [Member] | Capital markets
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Bank Deposit Sweep Income [Member] | Corporate/Other
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Bank Deposit Sweep Income [Member] | Private Client Division
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										117,422	116,052
Commissions From Sales And Trading [Member]
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										280,069	286,211
Commissions From Sales And Trading [Member] | Asset Management
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										0	0
Commissions From Sales And Trading [Member] | Capital markets
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										131,380	131,955
Commissions From Sales And Trading [Member] | Corporate/Other
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										28	89
Commissions From Sales And Trading [Member] | Private Client Division
Contracts with Customers Assets and Liabilities [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax										$ 148,661	$ 154,167

[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.