Leases (Maturities of lease liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Mar. 31, 2019
Finance Lease Liabilities Payments Due [Abstract]
2020	$ 231,189
2021	174,105
2022	132,805
2023	115,521
2024	82,385
Thereafter	59,460
Total lease payments	795,465
Less: imputed interest	0
Financing lease liability	795,465
Operating Lease Liabilities Payments Due [Abstract]
2020	23,585
2021	21,204
2022	20,354
2023	19,689
2024	12,195
Thereafter	67,422
Total lease payments	164,449
Less: inputed interest	(56,868)
Operating lease liability	$ 107,581	$ 0