Schedule of Other Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Mar. 31, 2012
Other Assets, Accrued Expenses, Other Current Liabilities, And Other Liabilities And Deferred Credits [Abstract]
Recoverable insurance losses	$ 3,422	$ 3,150
Deferred income tax assets	69,585	64,090
Deferred finance charges	5,510	6,797
Savings plans and supplemental plan	22,304	29,538
Noncurrent tax receivable	9,106	9,106
Other	3,915	5,173
Other assets	$ 113,842	$ 117,854