Unaudited Quarterly Financial Data (Unaudited Quarterly Financial Data) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Sales and other operating revenues	$ 607,496	$ 653,581	$ 488,248	$ 284,622	$ 650,030	$ 668,771	$ 456,942	$ 295,475
Gross profit	116,497	108,518	93,076	53,857	119,185	135,453	87,844	52,197
Net income	34,322	50,219	28,306	3,321	36,450	57,062	26,498	(7,504)	$ 116,168	$ 112,506	$ 118,148
Net income attributable to Universal Corporation	$ 30,518	$ 45,400	$ 26,167	$ 3,577	32,869	53,647	25,264	(5,476)	105,662	106,304	109,016
Earnings available to Universal Corporation common shareholders					$ (41,484)	$ 49,960	$ 21,577	$ (9,163)	$ 105,662	$ 20,890	$ 94,268
Basic	$ 1.21	$ 1.80	$ 1.03	$ 0.14	$ (1.64)	$ 2.17	$ 0.95	$ (0.40)	$ 4.18	$ 0.89	$ 4.16
Diluted	1.20	1.78	1.02	0.14	(1.64)	1.92	0.90	(0.40)	4.14	0.88	3.92
Preferred stock, cash dividends declared per share	0.00	0.00	0.00	0.00	0.00	16.88	16.87	16.88	0.00	50.63	67.50
Common stock, cash dividends declared per share	0.55	0.55	0.54	0.54	0.54	0.54	0.53	0.53	2.18	2.14	$ 2.10
Market price range of common stock, high	53.85	60.45	65.90	75.70	83.35	64.20	61.69	57.75	53.85	83.35
Market price range of common stock, low	$ 45.95	$ 52.05	$ 55.00	$ 63.15	$ 63.30	$ 52.40	$ 55.29	$ 52.26	$ 45.95	$ 63.30