Valuation and Qualifying Account - Allowance for Doubtful Accounts (Details) - SEC Schedule, 12-09, Allowance, Credit Loss [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Movement in Valuation Allowances and Reserves
Balance at Beginning of Period	$ 411		$ 513		$ 552
Credited to Costs and Expenses	0		150		0
Deductions	0	[1]	252	[2]	39	[3]
Balance at End of Period	411		411		513
AllianceBernstein L.P. [Member]
Movement in Valuation Allowances and Reserves
Amounts written-off as uncollectible	$ 0		$ 252		$ 39

[1] Includes accounts written-off as uncollectible of $0.

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

[3] Includes accounts written-off as uncollectible of $39.