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Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Employee Compensation Plans - Additional Information (Narrative) (Details)				12 Months Ended
	Feb. 23, 2017 shares	Jan. 26, 2017 shares	Jan. 06, 2017 shares	Dec. 31, 2016 USD ($) employee_compensation_plan shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Employee Compensation Plans Granted \| employee_compensation_plan				2
Maximum annual contribution under Defined Contribution Plan				$ 18,000	$ 18,000	$ 17,500
Employer contribution to Defined Contribution Plan				1,300,000	1,600,000	1,200,000
Deferred bonus amounts				$ 7,700,000	8,300,000	8,600,000
Vesting period of deferred bonus				5 years
Company-owned life insurance policy designed to offset a percentage of the EDCP liability				60.00%
Deferred compensation plans cost				$ 11,800,000	8,600,000	11,400,000
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Number of shares \| shares				408,207
Restricted Stock \| Class A Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value of ESP awards outstanding				$ 22,800,000
The aggregate intrinsic value of ESP awards that are expected to vest				22,000,000
Compensation expense relating to the share-based awards				5,200,000	4,600,000	5,600,000
Unrecognized compensation cost related to unvested share-based compensation				$ 8,300,000
Cost is expected to be recognized over a weighted average period				2 years 19 days
Number of shares of Class A Stock available \| shares				537,841
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense relating to the share-based awards				$ 19,900	69,900	133,600
Employee Stock Option \| Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period under share based payment	4 years 6 months
Number of Options, Granted \| shares	3,439
Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense relating to the share-based awards				$ 1,000,000	$ 1,800,000	$ 380,100
Cost is expected to be recognized over a weighted average period				2 years 3 months
Aggregate intrinsic value of OARs outstanding and expected to vest				$ 2,100,000
Liability related to the OARs				2,700,000
Total unrecognized compensation cost				$ 3,200,000
Stock Appreciation Rights [Member] \| Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period under share based payment			5 years
Number Of Stock Appreciation Rights Granted \| shares			443,630
Employee Share Plan \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period under share based payment				3 years
Employee Share Plan \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period under share based payment				5 years
Oppenheimer Holdings Inc. Stock Appreciation Right Plan \| Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period under share based payment				5 years
Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period				6 months
Equity Incentive Plan \| Class A Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term granted for options				5 years
Equity Incentive Plan \| Second Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage under share based payment				25.00%
Equity Incentive Plan \| Third Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage under share based payment				25.00%
Equity Incentive Plan \| Fourth Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage under share based payment				25.00%
Equity Incentive Plan \| Six Months Before Expiration
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage under share based payment				25.00%
Stock Incentive Plan 2014 \| Subsequent Event [Member] \| Class A Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period under share based payment	3 years	3 years
Granted, Number of shares \| shares	64,100	343,500
Stock Incentive Plan 2014 \| Subsequent Event [Member] \| Class A Stock \| Non Employee Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Number of shares \| shares	24,500
Next three years vesting percentage of shares	25.00%
Executive Deferred Compensation Plan and Deferred Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Company's deferred compensation liability				$ 49,700,000
CIBC Deferred Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Company's deferred compensation liability				$ 15,000,000