Debt Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Debt Disclosure [Abstract]
Interest and debt costs incurred, net of interest capitalized	$ 13,312	$ 12,239	$ 39,741	$ 37,927
Interest costs capitalized	2,513	3,638	8,280	9,920
Total interest and debt costs	$ 15,825	$ 15,877	$ 48,021	$ 47,847