CONDENSED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2019	Mar. 31, 2019	Sep. 04, 1993
Beneficial assignee certificate, par value (in dollars per share)	$ 10	$ 10	$ 10
Units of limited partnership interest, authorized	22,000,000	22,000,000	20,000,000
Units of limited partnership interest, issued	21,996,102	21,996,102
Units of limited partnership interest, outstanding	21,695,581	21,695,581
Series 15
Beneficial assignee certificate, par value (in dollars per share)	$ 10	$ 10
Units of limited partnership interest, authorized	22,000,000	22,000,000
Units of limited partnership interest, issued	3,870,500	3,870,500
Units of limited partnership interest, outstanding	3,810,700	3,810,700
Series 16
Beneficial assignee certificate, par value (in dollars per share)	$ 10	$ 10
Units of limited partnership interest, authorized	22,000,000	22,000,000
Units of limited partnership interest, issued	5,429,402	5,429,402
Units of limited partnership interest, outstanding	5,332,500	5,332,500
Series 17
Beneficial assignee certificate, par value (in dollars per share)	$ 10	$ 10
Units of limited partnership interest, authorized	22,000,000	22,000,000
Units of limited partnership interest, issued	5,000,000	5,000,000
Units of limited partnership interest, outstanding	4,938,247	4,938,247
Series 18
Beneficial assignee certificate, par value (in dollars per share)	$ 10	$ 10
Units of limited partnership interest, authorized	22,000,000	22,000,000
Units of limited partnership interest, issued	3,616,200	3,616,200
Units of limited partnership interest, outstanding	3,558,134	3,558,134
Series 19
Beneficial assignee certificate, par value (in dollars per share)	$ 10	$ 10
Units of limited partnership interest, authorized	22,000,000	22,000,000
Units of limited partnership interest, issued	4,080,000	4,080,000
Units of limited partnership interest, outstanding	4,056,000	4,056,000