Valuation and Qualifying Account - Allowance for Doubtful Accounts (Details) - AllianceBernstein L.P. - Allowance for Doubtful Accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Accounts written off as uncollectible	$ 218		$ 16		$ 252
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	395		411		513
Credited to Costs and Expenses	132		0		150
Deductions	218	[1]	16	[2]	252	[3]
Balance at End of Period	$ 309		$ 395		$ 411

[1] Includes accounts written-off as uncollectible of $218.

[2] Includes accounts written-off as uncollectible of $16.

[3] Includes accounts written-off as uncollectible of $252.