Organization and Significant Accounting Policies - Revenue by Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2020
Disaggregation of revenue
Revenue	$ 445,732	$ 394,912	$ 367,296
Contract Liability
Disaggregation of revenue
Revenue	3,144	5,468	1,670
Domestic
Disaggregation of revenue
Revenue	262,258	241,898	201,046
International
Disaggregation of revenue
Revenue	183,474	153,014	166,250
U.S. government
Disaggregation of revenue
Revenue	294,941	271,273	225,341
Non-U.S. government
Disaggregation of revenue
Revenue	150,791	123,639	141,955
FFP
Disaggregation of revenue
Revenue	346,092	307,413	269,917
CPFF
Disaggregation of revenue
Revenue	93,428	86,719	94,176
T&M
Disaggregation of revenue
Revenue	6,212	780	3,203
Small UAS
Disaggregation of revenue
Revenue	178,201	235,854	225,888
TMS
Disaggregation of revenue
Revenue	76,415	87,268	63,781
MUAS.
Disaggregation of revenue
Revenue	93,156	15,837
HAPS
Disaggregation of revenue
Revenue	43,325	42,426	60,864
Other.
Disaggregation of revenue
Revenue	$ 54,635	$ 13,527	$ 16,763