Leases (Maturities of lease liabilities) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019
Finance Lease Liabilities Payments Due [Abstract]
2020	$ 275,558
2021	196,972
2022	156,144
2023	124,371
2024	93,732
Thereafter	101,429
Total lease payments	948,206
Less: imputed interest	0
Financing lease liability	948,206
Operating Lease Liabilities Payments Due [Abstract]
2020	22,936
2021	19,879
2022	18,467
2023	17,740
2024	17,118
Thereafter	66,634
Total lease payments	162,774
Less: inputed interest	(57,766)
Operating lease liability	$ 105,008	$ 0