Fair Value Measurements (Rollforward of Earn-outs) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020	Oct. 01, 2019
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Option and purchase right	$ 7,739	$ 7,739
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring | Other Current Liabilities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Option and purchase right	$ (7,739)	$ (7,739)
Frontier [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Remaining percentage to be acquired			40.00%