Schedule of Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Accrued employee benefit plan costs	$ 19,705	$ 21,874
Stock based compensation	6,780	8,731
Net operating loss and tax credit carryforwards	6,177	2,327
Other	5,548	3,901
Gross deferred tax assets	38,210	36,833
Less valuation allowance	(4,705)	(17,829)
Net deferred tax assets	33,505	19,004
Depreciation and amortization	(33,505)	(19,004)
Gross deferred tax liabilities	$ (33,505)	$ (19,004)