Condensed Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net income	$ 430,418	$ 390,268
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization of deferred sales commissions	37,471	29,517
Non-cash long-term incentive compensation expense	12,122	15,032
Depreciation and other amortization	42,388	48,245
Unrealized losses on investments	37,438	11,719
Other, net	(11,067)	(9,860)
Changes in assets and liabilities:
Decrease in segregated cash and securities	94,693	474,343
(Increase) in receivables	(1,574)	(413,972)
Decrease (increase) in investments	38,959	(55,820)
(Increase) in deferred sales commissions	(27,862)	(73,265)
(Increase) in other assets	(64,041)	(17,582)
(Decrease) in payables	(125,494)	(214,782)
(Decrease) in accounts payable and accrued expenses	(15,240)	(33,571)
Increase in accrued compensation and benefits	356,083	295,248
Net cash provided by operating activities	804,294	445,520
Cash flows from investing activities:
Purchases of investments	(86)	(670)
Proceeds from sales of investments	4,189	140
Purchases of furniture, equipment and leasehold improvements	(17,084)	(19,626)
Proceeds from sales of furniture, equipment and leasehold improvements	36	240
Purchase of business, net of cash acquired	0	(60,610)
Net cash used in investing activities	(12,945)	(80,526)
Cash flows from financing activities:
(Repayment) issuance of commercial paper, net	(132,843)	90,931
Proceeds from bank loans	0	40,000
Increase (decrease) in overdrafts payable	17,781	(21,462)
Distributions to General Partner and Unitholders	(461,956)	(433,917)
Distributions to non-controlling interests in consolidated entities	(10,159)	(11,375)
Capital contributions from General Partner	947	1,282
Capital contributions to AB Holding	(733)	(1,411)
Payments of contingent payment arrangements/purchase of shares	(4,820)	(669)
Additional investments by AB Holding with proceeds from exercise of compensatory options to buy AB Holding Units	8,979	12,849
Purchases of AB Holding Units to fund long-term incentive compensation plan awards, net	(99,590)	(4,612)
Purchases of AB Units	(802)	(1,375)
Other	(20)	(27)
Net cash used in financing activities	(683,216)	(329,786)
Effect of exchange rate changes on cash and cash equivalents	(8,925)	(10,120)
Net increase in cash and cash equivalents	99,208	25,088
Cash and cash equivalents as of beginning of the period	555,503	509,891
Cash and cash equivalents as of end of the period	654,711	534,979
Non-cash investing activities:
Fair value of assets acquired	0	87,821
Fair value of liabilities assumed	0	1,342
Fair value of redeemable non-controlling interest recorded	0	16,504
Non-cash financing activities:
Payables recorded under contingent payment arrangements	$ 0	$ 9,365