Components of Interest Expense (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Interest expense, borrowings:
Interest expense	$ 18,532	$ 16,540	$ 54,401	$ 48,715
Capitalized interest	(162)	(119)	(432)	(290)
Amortization of transaction costs	1,106	1,014	2,800	3,149
Interest expense resulting from derivatives	4,131	4,641	13,284	16,106
Total interest expense	$ 23,607	$ 22,076	$ 70,053	$ 67,680