Leases (Right-of-use Assets and Lease Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Mar. 31, 2020
Leases [Abstract]
Operating Lease, Right-of-Use Asset	$ 99,258
Finance Lease, Right-of-Use Asset	$ 1,975
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentAbstract
Total right-of-use assets	$ 101,233
Current liabilities: Operating leases	30,813
Current liabilities: Finance leases	$ 577
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Long Term Debt Current
Noncurrent liabilities: Operating leases	$ 80,789
Noncurrent liabilities: Finance leases	$ 1,373
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Long-term Debt, Excluding Current Maturities
Total lease liabilities	$ 113,552