Fair Value of Financial Instruments - Contingent Consideration (Details) $ in Thousands	1 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jan. 03, 2020 USD ($)
Franklin Blackhorse, L.P | Other Assets
Assets and liabilities measured at fair value on a recurring basis
Income (Loss) from Equity Method Investments		$ 5,300
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Cash paid for initial investment			$ 5,000
Level 3
Change in fair value of our Level 3 contingent consideration
Balance at the Beginning period		10,874
Initial measurement recognized at acquisition		1,600
Total remeasurement (gain) loss recognized in earnings		(4,478)
Balance at the ending period		7,996	10,874
H4 Global
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration for certain goals		$ 2,700
Period for contingent consideration contracts		5 years
H4 Global | Level 3
Change in fair value of our Level 3 contingent consideration
Balance at the Beginning period		$ 1,073
Total remeasurement (gain) loss recognized in earnings		(509)
Balance at the ending period		$ 564	$ 1,073
H4 Global | Discount Rate
Assets and liabilities measured at fair value on a recurring basis
Measurement inputs for contingent consideration		0.230	0.235
Deltenna
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration for certain goals		$ 6,700
Deltenna | Level 3
Change in fair value of our Level 3 contingent consideration
Balance at the Beginning period		1,787
Total remeasurement (gain) loss recognized in earnings		1,023
Balance at the ending period		$ 2,810	$ 1,787
Deltenna | Volatility for underlying revenue metrics
Assets and liabilities measured at fair value on a recurring basis
Measurement inputs for contingent consideration		0.38	0.36
Deltenna | Discount Rate
Assets and liabilities measured at fair value on a recurring basis
Measurement inputs for contingent consideration		0.10	0.11
Shield Aviation
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration for certain goals		$ 10,000
Shield Aviation | Level 3
Change in fair value of our Level 3 contingent consideration
Balance at the Beginning period		3,814
Total remeasurement (gain) loss recognized in earnings		(792)
Balance at the ending period		$ 3,022	$ 3,814
Shield Aviation | Volatility for underlying revenue metrics
Assets and liabilities measured at fair value on a recurring basis
Measurement inputs for contingent consideration		0.32	0.18
Revenue risk adjustment used in determination of fair value of contingent consideration		13.00%	13.00%
Shield Aviation | Discount Rate
Assets and liabilities measured at fair value on a recurring basis
Measurement inputs for contingent consideration		0.097	0.036
Nuvotronics
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration for certain goals	$ 8,000	$ 8,000
Contingent consideration	$ 4,900
Period for contingent consideration contracts		12 months
Nuvotronics | Level 3
Change in fair value of our Level 3 contingent consideration
Balance at the Beginning period		$ 4,200
Total remeasurement (gain) loss recognized in earnings		$ (4,200)
Balance at the ending period			$ 4,200
Nuvotronics | Volatility for underlying revenue metrics
Assets and liabilities measured at fair value on a recurring basis
Measurement inputs for contingent consideration		0.137	0.124
Nuvotronics | Discount Rate
Assets and liabilities measured at fair value on a recurring basis
Measurement inputs for contingent consideration		0.074	0.074
Delerrok Inc.
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration for certain goals		$ 2,000
Contingent consideration				$ 1,600
Delerrok Inc. | Level 3
Change in fair value of our Level 3 contingent consideration
Initial measurement recognized at acquisition		1,600
Balance at the ending period		$ 1,600
Delerrok Inc. | Volatility for underlying revenue metrics
Assets and liabilities measured at fair value on a recurring basis
Measurement inputs for contingent consideration		0.110
Delerrok Inc. | Discount Rate
Assets and liabilities measured at fair value on a recurring basis
Measurement inputs for contingent consideration		0.047