Supplemental balance sheet information related to leases (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019
Operating lease right-of-use assets	$ 35,665	$ 39,256	$ 34,838
Current portion of operating lease liabilities	9,105	9,823	8,591
Long-term operating lease liabilities	22,813	25,893	23,331
Total operating lease liabilities	$ 31,918	$ 35,716	$ 31,922