Segment Information - Narrative (Details)	12 Months Ended
	Mar. 31, 2018 segment country
Segment Reporting Information [Line Items]
Number of countries in which tobacco is purchased (more than 35) | country	35
Number of countries to which tobacco is shipped | country	90
Number of geographical operating segments	5
Other Regions
Segment Reporting Information [Line Items]
Number of reportable segments	1
Africa, Asia, Europe and South America
Segment Reporting Information [Line Items]
Number of reportable segments	4