Leases (Maturities of lease liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Mar. 31, 2020
Finance Lease Liabilities Payments Due [Abstract]
2020	$ 183,067
2021	143,263
2022	121,509
2023	82,967
2024	60,569
Thereafter	20,775
Total lease payments	612,150
Less: imputed interest	0
Financing lease liability	612,150
Operating Lease Liabilities Payments Due [Abstract]
2020	24,731
2021	22,413
2022	21,605
2023	17,181
2024	5,717
Thereafter	64,484
Total lease payments	156,131
Less: inputed interest	(54,155)
Operating lease liability	$ 101,976	$ 106,443