Consolidated Statements of Earnings (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]
Revenues	$ 1,066,368us-gaap_SalesRevenueGoodsNet	$ 898,396us-gaap_SalesRevenueGoodsNet	$ 642,562us-gaap_SalesRevenueGoodsNet
Cost of Goods Sold	812,235us-gaap_CostOfGoodsSold	712,937us-gaap_CostOfGoodsSold	539,317us-gaap_CostOfGoodsSold
Gross Profit	254,133us-gaap_GrossProfit	185,459us-gaap_GrossProfit	103,245us-gaap_GrossProfit
Equity in Earnings of Unconsolidated Joint Venture	44,967	37,811	32,507
Corporate General and Administrative Expense	(30,751)us-gaap_GeneralAndAdministrativeExpense	(24,552)us-gaap_GeneralAndAdministrativeExpense	(23,918)us-gaap_GeneralAndAdministrativeExpense
Other Operating Income (Loss)	3,201us-gaap_OtherOperatingIncomeExpenseNet	1,368us-gaap_OtherOperatingIncomeExpenseNet	(1,232)us-gaap_OtherOperatingIncomeExpenseNet
Acquisition and Litigation Expense	(6,880)exp_AcquisitionAndLitigationExpense		(10,683)exp_AcquisitionAndLitigationExpense
Interest Expense, Net	(11,743)us-gaap_InterestExpense	(18,282)us-gaap_InterestExpense	(15,823)us-gaap_InterestExpense
Earnings before Income Taxes	252,927	181,804	84,096
Income Taxes	(66,074)us-gaap_IncomeTaxExpenseBenefit	(57,561)us-gaap_IncomeTaxExpenseBenefit	(26,352)us-gaap_IncomeTaxExpenseBenefit
Net Earnings	$ 186,853us-gaap_NetIncomeLoss	$ 124,243us-gaap_NetIncomeLoss	$ 57,744us-gaap_NetIncomeLoss
EARNINGS PER SHARE
Basic	$ 3.77us-gaap_EarningsPerShareBasic	$ 2.53us-gaap_EarningsPerShareBasic	$ 1.24us-gaap_EarningsPerShareBasic
Diluted	$ 3.71us-gaap_EarningsPerShareDiluted	$ 2.49us-gaap_EarningsPerShareDiluted	$ 1.22us-gaap_EarningsPerShareDiluted
AVERAGE SHARES OUTSTANDING
Basic	49,604,249	49,090,750	46,622,646
Diluted	50,372,243	49,939,165	47,340,450
CASH DIVIDENDS PER SHARE	$ 0.40	$ 0.40	$ 0.40

Acquisition and litigation expense.

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Aggregate dividends paid during the period for each share of common stock outstanding.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of the cost of borrowed funds accounted for as interest expense.

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