Fair Value of Financial Instruments - Contingent Consideration (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019 USD ($) item	Sep. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Jul. 31, 2018 USD ($)
Franklin Blackhorse, L.P | Other Assets
Assets and liabilities measured at fair value on a recurring basis
Income (Loss) from Equity Method Investments	$ 5,200
Level 2
Debt instruments
Fair Value	204,000	$ 203,300
Carrying value	200,000	200,000
Level 3
Change in fair value of our Level 3 contingent consideration
Balance at the Beginning period	10,874
Total remeasurement (gain) loss recognized in earnings	(3,005)
Balance at the ending period	$ 7,869	10,874
Investment Assets | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Cash paid for initial investment		$ (5,000)
H4 Global
Assets and liabilities measured at fair value on a recurring basis
Period for contingent consideration contracts	5 years	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	(245)
Balance at the ending period	828	$ 1,073
H4 Global | Maximum
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration	2,900
Receivable for estimated earn-out amount due from purchaser	2,900
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	1,213
Balance at the ending period	3,000	$ 1,787
Deltenna | Maximum
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration	$ 7,200
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
Determination of fair value of contingent consideration | item	1,000,000
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	227
Balance at the ending period	4,041	$ 3,814
Shield Aviation | Maximum
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration	$ 10,000			$ 10,000
Shield Aviation | Volatility for underlying revenue metrics
Assets and liabilities measured at fair value on a recurring basis
Measurement inputs for contingent consideration	0.18	0.18
Revenue risk adjustment used in determination of fair value of contingent consideration	14.00%	13.00%
Shield Aviation | Discount Rate
Assets and liabilities measured at fair value on a recurring basis
Measurement inputs for contingent consideration	0.033	0.036
Nuvotronics
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration			$ 4,900
Determination of fair value of contingent consideration | item	1,000,000
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 | Maximum
Assets and liabilities measured at fair value on a recurring basis
Contingent consideration	$ 8,000		$ 8,000
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