Long-term Debt - Aggregate Maturities of Long-Term Debt (Detail 3) - USD ($) $ in Thousands	Mar. 31, 2018	Jun. 30, 2017
Long Term Debt [Abstract]
2018	$ 94,438
2019	107,930
2020	890,525
Principal amount of long-term debt	1,092,893	$ 1,243,867
Less unamortized debt issuance costs	(8,993)	(12,304)
Total long-term debt	$ 1,083,900	$ 1,231,563