Stockholders' Equity and Noncontrolling Interests - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jul. 17, 2015	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Class of Stock [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award Options Non Vested Stock Outstanding Weighted Average Remaining Contractual Term		22 months
Preferred stock, shares issued (in shares)		0	0
Preferred stock, shares outstanding (in shares)		0	0
Shares issued from treasury stock to settle conversion premium on Convertible Notes	1,889,431		1,889,431	1,889,431
Preferred stock, shares authorized (in shares)		1,000,000	1,000,000
Preferred stock, par value (usd per share)		$ 0.01	$ 0.01
Number of shares of common stock purchased		1,756,831	1,756,831	3,216,654
Repurchased common stock value		$ 121,191		$ 178,244
Treasury stock, shares (in shares)		12,680,105	10,923,274
Accelerated Share Repurchase Agreement [Member]
Class of Stock [Line Items]
Stock Repurchased and Retired During Period, Shares		1,495,714		2,961,444
Accelerated Share Repurchases, Settlement (Payment) or Receipt		$ 100		$ 166,392
Accelerated Share Repurchases, Final Price Paid Per Share		$ 66.86		$ 56.19