Leases (Maturities of lease liabilities) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Mar. 31, 2021
Finance Lease Liabilities Payments Due [Abstract]
2022	$ 168,277
2023	132,482
2024	98,586
2025	68,555
2026	35,679
Thereafter	0
Total lease payments	503,579
Less: imputed interest	(35,095)
Present value of finance lease liabilities	468,484
Operating Lease Liabilities Payments Due [Abstract]
2022	24,926
2023	22,560
2024	21,418
2025	6,414
2026	3,560
Thereafter	61,302
Total lease payments	140,180
Less: inputed interest	(50,790)
Present value of operating lease liabilities	$ 89,390	$ 92,510