Summary of Significant Accounting Policies - Additional Information (Details)		1 Months Ended		3 Months Ended												12 Months Ended
	Feb. 14, 2017 $ / shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2016 USD ($) $ / shares	Sep. 30, 2016 $ / shares	Jun. 30, 2016 $ / shares	Mar. 31, 2016 $ / shares	Dec. 31, 2015 USD ($) $ / shares		Sep. 30, 2015 $ / shares	[1],[2],[3]	Jun. 30, 2015 $ / shares	[1],[2],[3]	Mar. 31, 2015 $ / shares	[1],[2],[3]	Dec. 31, 2016 USD ($) investment shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($)
Collateralized Securities Transactions [Abstract]
Cash on deposit with clearing organizations for trade facilitation purposes		$ 41,700,000	$ 81,400,000	$ 41,700,000				$ 81,400,000								$ 41,700,000	$ 81,400,000
SCB LLC held U.S. Treasury Bills		$ 28,900,000	$ 24,900,000	$ 28,900,000				$ 24,900,000								$ 28,900,000	$ 24,900,000
Schedule of Equity Method Investments [Line Items]
Private equity investments owned outside of consolidated venture capital fund | investment																2
Deferred Sales Commissions, Net [Abstract]
Period of time the deferred sales commissions are amortized over for U.S. fund shares																5 years 6 months
Period of time the deferred sales commissions are amortized over for non-U.S. fund shares																4 years
Mutual Fund Underwriting Activities [Abstract]
Period over which receivables from brokers and dealers for sale of shares of company-sponsored mutual funds generally are realized																3 days
Long-term Incentive Compensation Plans [Abstract]
Employee allocation percentage maximum, percent		50.00%		50.00%												50.00%
Long-term incentive cash maximum per employee		$ 250,000		$ 250,000												$ 250,000
Long-term incentive awards vesting periods																4 years
Period over which holding units are typically distributed to Directors																3 years
AB Holding Units purchased in periods (in units) | shares																10,500,000	8,500,000
Dollar amount paid for AB Holding Units acquired																$ 236,600,000	$ 218,300,000
Open-market purchases of AB Holding Units (in units) | shares																7,900,000	5,800,000
Dollar amount paid for open-market purchases of AB Holding Units																$ 176,100,000	$ 151,100,000
Restricted AB Holding Units awarded to employees (in units) | shares		6,100,000	7,000,000													7,000,000	7,400,000
Units issued upon exercise of options (in units) | shares																358,262	541,073
Proceeds from stock options exercised																$ 6,108,000	$ 9,233,000	$ 18,955,000
Foreign Currency Translations [Abstract]
Net foreign currency transaction gains (losses)																$ 1,100,000	1,000,000	(1,600,000)
Cash Distribution [Line Items]
Cash distribution, distribution declared (in dollars per unit) | $ / shares				$ 0.73	$ 0.51	$ 0.46	$ 0.45	$ 0.56	[1],[2],[3]	$ 0.50		$ 0.54		$ 0.51
Percentage of General Partnership interest in company																1.00%
Cash distributions per unit paid to the General Partner and Unitholders (in dollars per unit)																$ 1.98	$ 2.18	$ 2.11
Cash Distribution [Member]
Cash Distribution [Line Items]
Cash distribution, declaration date																Feb. 14, 2017
Percentage of General Partnership interest in company																1.00%
Cash distribution, distribution date																Mar. 09, 2017
Cash distribution, date of record																Feb. 24, 2017
Employees Based Outside of the United States [Member]
Long-term Incentive Compensation Plans [Abstract]
Employee allocation percentage maximum, percent		100.00%		100.00%												100.00%
Long-term incentive cash maximum per employee		$ 100,000		$ 100,000												$ 100,000
Subsequent Event [Member] | Cash Distribution [Member]
Cash Distribution [Line Items]
Cash distribution, distribution declared (in dollars per unit) | $ / shares	$ 0.73
Furniture [Member]
Furniture, Equipment and Leasehold Improvements [Abstract]
Useful Life																8 years
Equipment [Member] | Minimum [Member]
Furniture, Equipment and Leasehold Improvements [Abstract]
Useful Life																3 years
Equipment [Member] | Maximum [Member]
Furniture, Equipment and Leasehold Improvements [Abstract]
Useful Life																6 years
Consolidated Private Equity Fund [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage		10.00%		10.00%												10.00%

[1] Cash distributions reflect the impact of our non-GAAP adjustments.

[2] Certain prior-period amounts have been revised, see Note 2 for a discussion of the revision.

[3] Declared and paid during the following quarter.