Condensed Statement of Changes in Partners' Capital - USD ($) $ in Thousands	Total	AB Holding Units held by AB to fund long-term incentive compensation plans	Accumulated Other Comprehensive (Loss) Income	General Partner	Limited Partner
Balance, beginning of period at Dec. 31, 2018		$ (27,759)	$ (39,461)	$ 1,385	$ 1,555,892
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 98,713			103	98,610
Cash distributions to Unitholders				(113)	(108,055)
Retirement of AB Holding Units					(73,383)
Issuance of AB Holding Units to fund long-term incentive compensation plan awards					60,903
Exercise of compensatory options to buy AB Holding Units					8,951
Change in AB Holding Units held by AB to fund long-term incentive compensation plans		(7,987)
Foreign currency translation adjustment, net of tax			114
Changes in employee benefit related items, net of tax			217
Balance, end of period at Jun. 30, 2019	1,469,417	(35,746)	(39,130)	1,375	1,542,918
Balance, beginning of period at Mar. 31, 2019		(24,464)	(38,018)	1,370	1,490,581
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	52,274			55	52,219
Cash distributions to Unitholders				(50)	(47,311)
Retirement of AB Holding Units					(3,730)
Issuance of AB Holding Units to fund long-term incentive compensation plan awards					49,590
Exercise of compensatory options to buy AB Holding Units					1,569
Change in AB Holding Units held by AB to fund long-term incentive compensation plans		(11,282)
Foreign currency translation adjustment, net of tax			(1,036)
Changes in employee benefit related items, net of tax			(76)
Balance, end of period at Jun. 30, 2019	1,469,417	(35,746)	(39,130)	1,375	1,542,918
Balance, beginning of period at Dec. 31, 2019	1,552,538	(27,436)	(40,628)	1,402	1,619,200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	119,185			121	119,064
Cash distributions to Unitholders				(149)	(145,381)
Retirement of AB Holding Units					(46,178)
Issuance of AB Holding Units to fund long-term incentive compensation plan awards	9,961				9,961
Exercise of compensatory options to buy AB Holding Units					147
Change in AB Holding Units held by AB to fund long-term incentive compensation plans		1,234
Foreign currency translation adjustment, net of tax			(5,076)
Changes in employee benefit related items, net of tax			441
Balance, end of period at Jun. 30, 2020	1,486,722	(26,202)	(45,263)	1,374	1,556,813
Balance, beginning of period at Mar. 31, 2020		(29,002)	(48,105)	1,380	1,592,161
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	56,926			59	56,867
Cash distributions to Unitholders				(65)	(61,760)
Retirement of AB Holding Units					(31,958)
Issuance of AB Holding Units to fund long-term incentive compensation plan awards					1,503
Exercise of compensatory options to buy AB Holding Units					0
Change in AB Holding Units held by AB to fund long-term incentive compensation plans		2,800
Foreign currency translation adjustment, net of tax			2,545
Changes in employee benefit related items, net of tax			297
Balance, end of period at Jun. 30, 2020	$ 1,486,722	$ (26,202)	$ (45,263)	$ 1,374	$ 1,556,813