Net Income Per Common Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended			6 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Net Income Per Share [Line Items]
Aggregate principal amount of convertible notes settled		$ 167,800		$ 167,800
Conversion price, per share of common stock		$ 51.24		$ 51.24
Calculation of diluted net income per common share includes, effect of shares related to conversion spread of Convertible Notes		2,400,000
Dilutive common shares excluded from net loss per common share computations			5,100,000	3,700,000	5,100,000
Repayment of convertible notes in cash				$ 90,994	$ 1
Scenario, Forecast [Member]
Net Income Per Share [Line Items]
Aggregate principal amount of convertible notes settled	$ 167,800
Repayment of convertible notes in cash	$ 167,800
Common stock, shares issued on redemption of convertible notes	1,769,609