The consolidated number of office locations.

No definition available.

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- Definition

The number of office locations during the period.

+ References

No definition available.

+ Details

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- Definition

The percentage of office space subleased.

+ References

No definition available.

+ Details

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- Definition

The percentage of office space to be subleased.

+ References

No definition available.

+ Details

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- Definition

Amount recognized for the passage of time, typically for liabilities, that have been discounted to their net present values. Excludes accretion associated with asset retirement obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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- Definition

Area of a real estate property.

+ References

No definition available.

+ Details

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- Definition

Amount of other expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses associated with a discontinued operation or an asset retirement obligation.

+ References

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-Name Staff Accounting Bulletin (SAB)

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-Section P

-Subsection 3, 4

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- Definition

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

+ References

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

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- Definition

Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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Amount of any reversal and other adjustment made during the period to the amount of a previously accrued liability for a specified type of restructuring cost, excluding adjustments for costs incurred during the period, costs settled during the period, and foreign currency translation adjustments.

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Real Estate Charges (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Sep. 30, 2012 sqft	Dec. 31, 2014	Dec. 31, 2010 sqft Location
Real Estate Charges [Abstract]
Area of office space to be sub-leased (in square feet)			510,000us-gaap_AreaOfRealEstateProperty		380,000us-gaap_AreaOfRealEstateProperty
Portion of office space subleased (in hundredths)			90.00%ablp_PortionOfOfficeSpaceSubleased
Consolidated number of office locations in New York					2
Number of Locations					3ablp_NumberOfLocations
Portion of office space to be subleased in New York (in hundredths)			70.00%ablp_PortionOfOfficeSpaceToBeSubleased
Pre-Tax real estate credits	$ 383us-gaap_OtherRestructuringCosts	$ (1,942)us-gaap_OtherRestructuringCosts
Real estate liability restructuring reserve [Abstract]
Balance as of beginning of period	148,429us-gaap_RestructuringReserve	199,527us-gaap_RestructuringReserve		199,527us-gaap_RestructuringReserve
Expense (credit) incurred	139us-gaap_RestructuringCharges			(4,755)us-gaap_RestructuringCharges
Deferred rent	0			0
Payments made	(11,562)us-gaap_PaymentsForRestructuring			(50,893)us-gaap_PaymentsForRestructuring
Interest accretion	1,082us-gaap_AccretionExpense			4,550us-gaap_AccretionExpense
Balance as of end of period	$ 138,088us-gaap_RestructuringReserve			$ 148,429us-gaap_RestructuringReserve