Shareholder Rights Plan - Additional Information (Detail)	6 Months Ended
	Sep. 30, 2015 $ / shares
Equity [Abstract]
Shareholder rights expiration date	Feb. 10, 2022
Shareholder rights exercise price	$ 118
Shareholder Rights Plan, description of acquired entity	Shareholder Rights Plan provides that if a person or group acquires 15% or more of the Company's common stock
Shareholder Rights Plan, percentage of acquired entity	15.00%
Shareholder Rights Plan, description of merged entity	Company is thereafter merged into another entity, or if 50% or more of the Company's consolidated assets or earning power are sold, then the right will entitle its holder to buy common shares of the acquiring entity having a market value equal to two times the then-current exercise price of the right.
Shareholder Rights Plan, percentage of merged entity	50.00%