Revenue Recognition (Tables)

12 Months Ended

Dec. 31, 2018

Revenue From Contract With Customer [Abstract]

Schedule of Company's Total Revenues by Category for each Reportable Segment

The following table presents the Company’s total revenues by category for each reportable segment:

years ended December 31	Products and Services		Freight		Total
(add 000)	2018
Mid-America Group	$	1,133,754	$	89,482	$	1,223,236
Southeast Group		409,543		13,839		423,382
West Group		2,168,418		141,506		2,309,924
Total Building Materials Business		3,711,715		244,827		3,956,542
Magnesia Specialties		268,636		19,087		287,723
Total	$	3,980,351	$	263,914	$	4,244,265
	2017
Mid-America Group	$	982,214	$	71,112	$	1,053,326
Southeast Group		348,675		13,880		362,555
West Group		2,139,867		139,856		2,279,723
Total Building Materials Business		3,470,756		224,848		3,695,604
Magnesia Specialties		252,722		17,268		269,990
Total	$	3,723,478	$	242,116	$	3,965,594
	2016
Mid-America Group	$	945,193	$	71,905	$	1,017,098
Southeast Group		304,722		16,356		321,078
West Group		2,086,351		137,164		2,223,515
Total Building Materials Business		3,336,266		225,425		3,561,691
Magnesia Specialties		242,384		14,674		257,058
Total	$	3,578,650	$	240,099	$	3,818,749

Summary of Information About the Company's Contract Balances

The following table presents information about the Company’s contract balances:

December 31
(add 000)	2018		2017
Costs in excess of billings	$	1,975	$	1,310
Billings in excess of costs	$	6,743	$	7,204