Operating segments are defined as components of an enterprise that engage in business activities that earn revenue, incur expenses, and prepare separate financial information that is evaluated regularly by our chief operating decision maker in order to allocate resources and assess performance.

We are a leading supplier of heavy construction materials and light building materials in the United States. Our primary products are commodities that are essential in commercial and residential construction; public construction projects; and projects to build, expand, and repair roads and highways. Demand for our products is generally cyclical and seasonal, depending on economic and geographic conditions. We distribute our products across many United States markets, which provides us with regional economic diversification. We also produce sand used in hydraulic fracturing as part of our Oil and Gas Proppants segment.

Our business is organized into three sectors within which there are five reportable business segments. The Heavy Materials sector includes the Cement and Concrete and Aggregates segments. The Light Materials sector includes the Gypsum Wallboard and Recycled Paperboard segments. The Oil and Gas Proppants segment produces frac sand used in oil and gas extraction.

Our operations are conducted in the U.S. and include the mining of limestone for the manufacture, production, distribution, and sale of portland cement (a basic construction material which is the essential binding ingredient in concrete); the grinding and sale of slag; the mining of gypsum for the manufacture and sale of gypsum wallboard; the manufacture and sale of recycled paperboard to the gypsum wallboard industry and other paperboard converters; the sale of readymix concrete; the mining and sale of aggregates (crushed stone, sand, and gravel) and the mining and sale of sand used in hydraulic fracturing (frac sand).

We operate eight modern cement plants (one of which is operated through a joint venture located in Buda, Texas), one slag grinding facility, and 29 cement distribution terminals. Our cement companies focus on the U.S. heartland and operate as an integrated network selling product primarily in California, Colorado, Illinois, Indiana, Iowa, Kentucky, Missouri, Nebraska, Nevada, Ohio, Oklahoma, and Texas. We operate 23 readymix concrete batch plants and four aggregates processing plants in markets that are complementary to our cement network. On April 17, 2020 we sold our Concrete and Aggregates companies in northern California. See Footnote (D) for more information about the sale.

We operate five gypsum wallboard plants and a recycled paperboard mill. We distribute gypsum wallboard and recycled paperboard throughout the continental U.S., with the exception of the Northeast.

Our Oil and Gas Proppants business owns two frac sand processing facilities, four frac sand drying facilities, and two frac sand trans-load locations. Frac sand is sold into shale deposits across the United States. During May 2020, we significantly curtailed our operating activities at our frac sand facilities.

We account for intersegment sales at market prices. For segment reporting purposes only, we proportionately consolidate our 50% share of the Joint Venture Revenue and Operating Earnings, consistent with the way management reports the segments within the Company for making operating decisions and assessing performance.

The following table sets forth certain financial information relating to our operations by segment. We do not allocate interest or taxes at the segment level; these costs are disclosed at the consolidated company level.

	For the Three Months Ended June 30,
	2020			2019
	(dollars in thousands)
Revenue -
Cement	$	261,411		$	195,313
Concrete and Aggregates		44,190			39,778
Gypsum Wallboard		130,150			126,724
Paperboard		36,744			42,700
Oil and Gas Proppants		1,031			15,232
		473,526			419,747
Less: Intersegment Revenue		(20,206	)		(21,645	)
Less: Joint Venture Revenue		(25,300	)		(27,505	)
	$	428,020		$	370,597

	For the Three Months Ended June 30,
	2020		2019
	(dollars in thousands)
Intersegment Revenue -
Cement	$	6,031	$	4,253
Concrete and Aggregates		106		377
Paperboard		14,069		17,015
	$	20,206	$	21,645
Cement Sales Volume (M tons) -
Wholly Owned		1,866		1,318
Joint Venture		219		232
		2,085		1,550

	For the Three Months Ended June 30,
	2020			2019
	(dollars in thousands)
Operating Earnings -
Cement	$	60,455		$	36,121
Concrete and Aggregates		5,418			4,434
Gypsum Wallboard		41,325			37,932
Paperboard		2,895			9,944
Oil and Gas Proppants		(1,318	)		(3,670	)
Sub-Total		108,775			84,761
Corporate General and Administrative Expense		(17,789	)		(21,254	)
Gain on Sale of Businesses		51,973			—
Other Non-Operating Income (Loss)		(127	)		200
Earnings Before Interest and Income Taxes		142,832			63,707
Interest Expense, net		(14,041	)		(8,846	)
Earnings Before Income Taxes	$	128,791		$	54,861
Cement Operating Earnings -
Wholly Owned	$	52,659		$	26,689
Joint Ventures		7,796			9,432
	$	60,455		$	36,121
Capital Expenditures -
Cement	$	10,348		$	10,537
Concrete and Aggregates		1,261			595
Gypsum Wallboard		6,512			1,931
Paperboard		7,870			12,360
Oil and Gas Proppants		—			65
Other, net		—			—
	$	25,991		$	25,488
Depreciation, Depletion, and Amortization -
Cement	$	19,243		$	14,218
Concrete and Aggregates		2,721			2,191
Gypsum Wallboard		5,200			4,952
Paperboard		3,352			2,163
Oil and Gas Proppants		121			3,839
Corporate and Other		1,300			597
	$	31,937		$	27,960

	June 30,		March 31,
	2020		2020
	(dollars in thousands)
Identifiable Assets
Cement	$	1,999,175	$	1,980,306
Concrete and Aggregates		99,298		136,041
Gypsum Wallboard		372,628		375,946
Paperboard		187,511		183,288
Oil and Gas Proppants		8,047		14,294
Other, net		348,505		271,145
	$	3,015,164	$	2,961,020

The capital expenditures for the three months ended June 30, 2019 disclosed above differs from the capital expenditures on the Unaudited Consolidated Statement of Cash Flows as it includes $3.7 million of capital expenditures that were accrued at June 30, 2019 and therefore not included in the Statement of Cash Flows. See Footnote (B) for more information.

Segment operating earnings, including the proportionately consolidated 50% interest in the revenue and expenses of the Joint Venture, represent Revenue, less direct operating expenses, segment Depreciation, and segment Selling, General and Administrative expenses. We account for intersegment sales at market prices. Corporate assets consist primarily of cash and cash equivalents, general office assets, and miscellaneous other assets.

The basis used to disclose Identifiable Assets; Capital Expenditures; and Depreciation, Depletion, and Amortization conforms with the equity method, and is similar to how we disclose these accounts in our Unaudited Consolidated Balance Sheets and Unaudited Consolidated Statements of Earnings

Summarized financial information for the Joint Venture that is not consolidated is set out below (this summarized financial information includes the total amount for the Joint Venture and not our 50% interest in those amounts):