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	$ 158,541			166	158,375
Cash distributions to Unitholders				(169)	(162,026)
Retirement of AB Holding Units					(92,412)
Issuance of AB Holding Units to fund long-term incentive compensation plan awards					60,921
Exercise of compensatory options to buy AB Holding Units					9,642
Change in AB Holding Units held by AB to fund long-term incentive compensation plans		(6,157)
Foreign currency translation adjustment, net of tax			(4,279)
Changes in employee benefit related items, net of tax			484
Balance, end of period at Sep. 30, 2019	1,454,602	(33,916)	(43,256)	1,382	1,530,392
Balance, beginning of period at Jun. 30, 2019		(35,746)	(39,130)	1,375	1,542,918
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	59,828			63	59,765
Cash distributions to Unitholders				(56)	(53,971)
Retirement of AB Holding Units					(19,029)
Issuance of AB Holding Units to fund long-term incentive compensation plan awards					18
Exercise of compensatory options to buy AB Holding Units					691
Change in AB Holding Units held by AB to fund long-term incentive compensation plans		1,830
Foreign currency translation adjustment, net of tax			(4,393)
Changes in employee benefit related items, net of tax			267
Balance, end of period at Sep. 30, 2019	1,454,602	(33,916)	(43,256)	1,382	1,530,392
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	186,184			192	185,992
Cash distributions to Unitholders				(210)	(204,258)
Retirement of AB Holding Units					(54,823)
Issuance of AB Holding Units to fund long-term incentive compensation plan awards	10,243				10,243
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		4,745
Foreign currency translation adjustment, net of tax			834
Changes in employee benefit related items, net of tax			592
Balance, end of period at Sep. 30, 2020	1,495,992	(22,691)	(39,202)	1,384	1,556,501
Balance, beginning of period at Jun. 30, 2020		(26,202)	(45,263)	1,374	1,556,813
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	66,999			71	66,928
Cash distributions to Unitholders				(61)	(58,877)
Retirement of AB Holding Units					(8,645)
Issuance of AB Holding Units to fund long-term incentive compensation plan awards					282
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		3,511
Foreign currency translation adjustment, net of tax			5,910
Changes in employee benefit related items, net of tax			151
Balance, end of period at Sep. 30, 2020	$ 1,495,992	$ (22,691)	$ (39,202)	$ 1,384	$ 1,556,501