Share-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Dec. 31, 2015	Jun. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding at June 30, 2015, Shares	837,398
Granted, Shares	0
Exercised, Shares	(103,953)
Forfeited or expired, Shares	(17,938)
Outstanding at December 31, 2015, Shares	715,507	837,398
Exercisable at December 31, 2015, Shares	583,222
Outstanding at June 30, 2015, Weighted Average Exercise Price Per Share	$ 70.40
Granted, Weighted Average Exercise Price Per Share	0.00
Exercised, Weighted Average Exercise Price Per Share	55.67
Forfeited or expired, Weighted Average Exercise Price Per Share	80.24
Outstanding at December 31, 2015, Weighted Average Exercise Price Per Share	72.79	$ 70.40
Exercisable at December 31, 2015, Weighted Average Exercise Price Per Share	$ 73.61
Outstanding, Weighted Average Remaining Contractual Term (Years)	5 years 1 month 28 days	5 years 7 months 13 days
Exercisable at September 30, 2015, Weighted Average Remaining Contractual Term (Years)	4 years 7 months 2 days
Outstanding at June 30, 2015, Aggregate Intrinsic Value	$ 40,864
Outstanding at December 31, 2015, Aggregate Intrinsic Value	20,454	$ 40,864
Exercisable at December 31, 2015, Aggregate Intrinsic Value	$ 16,642