Components of Basic and Diluted Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share [Abstract]
Net loss available to common shareholders		$ (178,490)	$ (43,835)	$ (267,587)	$ (58,887)
Weighted average outstanding shares of common stock, basic		47,067,864	46,942,950	47,067,790	46,962,242
Weighted average common stock and equivalents		47,067,864	46,942,950	47,067,790	46,962,242
Loss per share, basic	[1]	$ (3.79)	$ (0.93)	$ (5.69)	$ (1.25)
Loss per share, diluted	[2]	$ (3.79)	$ (0.93)	$ (5.69)	$ (1.25)
Antidilutive incremental options and restricted stock awards and units		525,161	317,518	508,989	306,727

[1] The company calculates “Loss per share, basic” by dividing “Net loss available to common shareholders” by “Weighted average outstanding shares of common stock, basic”.

[2] The company calculates “Loss per share, diluted” by dividing “Net loss available to common shareholders” by “Weighted average common stock and equivalents”. As a result of the net losses incurred, the company has excluded the antidilutive effect of incremental share equivalents related to options, restricted stock awards and restricted stock units from the “Loss per share, diluted” calculation for the quarters and six month periods ended September 30, 2016 and 2015.