Schedule of Fixed Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Mar. 31, 2016
Fixed assets:
Total cost	$ 654,171	$ 643,457
Less: accumulated depreciation and amortization	(488,406)	(480,152)
Fixed assets, net	165,765	163,305
Equipment
Fixed assets:
Total cost	156,060	150,259
Software
Fixed assets:
Total cost	296,703	293,844
Leasehold improvements
Fixed assets:
Total cost	$ 201,408	$ 199,354