Revenue Recognition (Tables)

9 Months Ended

Sep. 30, 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:

	Three-Months Ended
	September 30, 2018
(Dollars in Thousands)	Products and Services		Freight		Total
Mid-America Group	$	348,429	$	28,576	$	377,005
Southeast Group		121,661		3,886		125,547
West Group		603,763		39,802		643,565
Total Building Materials Business		1,073,853		72,264		1,146,117
Magnesia Specialties		68,365		5,158		73,523
Total	$	1,142,218	$	77,422	$	1,219,640
	Three-Months Ended
	September 30, 2017
(Dollars in Thousands)	Products and Services		Freight		Total
Mid-America Group	$	287,085	$	21,387	$	308,472
Southeast Group		91,427		3,416		94,843
West Group		584,086		36,426		620,512
Total Building Materials Business		962,598		61,229		1,023,827
Magnesia Specialties		59,889		4,016		63,905
Total	$	1,022,487	$	65,245	$	1,087,732

2. Revenue Recognition (continued)

	Nine-Months Ended
	September 30, 2018
(Dollars in Thousands)	Products and Services		Freight		Total
Mid-America Group	$	841,897	$	64,480	$	906,377
Southeast Group		308,306		10,443		318,749
West Group		1,672,707		110,467		1,783,174
Total Building Materials Business		2,822,910		185,390		3,008,300
Magnesia Specialties		201,390		14,357		215,747
Total	$	3,024,300	$	199,747	$	3,224,047
	Nine-Months Ended
	September 30, 2017
(Dollars in Thousands)	Products and Services		Freight		Total
Mid-America Group	$	734,406	$	53,984	$	788,390
Southeast Group		266,690		10,784		277,474
West Group		1,620,632		106,110		1,726,742
Total Building Materials Business		2,621,728		170,878		2,792,606
Magnesia Specialties		189,918		12,592		202,510
Total	$	2,811,646	$	183,470	$	2,995,116

Summary of Information About the Company's Contract Balances

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

(Dollars in Thousands)	September 30, 2018		December 31, 2017		September 30, 2017
Costs in excess of billings	$	5,581	$	1,310	$	8,727
Billings in excess of costs	$	9,111	$	7,204	$	5,981