Retirement Benefits - Components of Net Periodic Benefit Cost (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 9 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2015
Mar. 31, 2014
Compensation and Retirement Disclosure [Abstract]        
Service cost $ 908 $ 632 $ 2,935 $ 1,876
Interest cost 1,591 1,806 4,975 5,389
Expected return on plan assets (60) (66) (189) (192)
Amortization of prior service cost 243 251 730 751
Amortization of net loss 918 764 2,847 2,278
Settlement/Curtailment (845) 0 (454) 0
Net periodic benefit cost $ 2,755 $ 3,387 $ 10,844 $ 10,102