Revenue Recognition (Tables)

3 Months Ended

Mar. 31, 2019

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
	March 31, 2019
(Dollars in Thousands)	Products and Services		Freight		Total
Mid-America Group	$	230,308	$	18,505	$	248,813
Southeast Group		115,312		3,925		119,237
West Group		463,511		33,320		496,831
Total Building Materials Business		809,131		55,750		864,881
Magnesia Specialties		69,174		4,900		74,074
Total	$	878,305	$	60,650	$	938,955
	Three Months Ended
	March 31, 2018
(Dollars in Thousands)	Products and Services		Freight		Total
Mid-America Group	$	167,890	$	10,891	$	178,781
Southeast Group		77,563		2,676		80,239
West Group		442,983		30,739		473,722
Total Building Materials Business		688,436		44,306		732,742
Magnesia Specialties		64,869		4,393		69,262
Total	$	753,305	$	48,699	$	802,004

Summary of Information About the Company's Contract Balances

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

(Dollars in Thousands)	March 31, 2019		December 31, 2018
Costs in excess of billings	$	2,238	$	1,975
Billings in excess of costs	$	5,814	$	6,743