Revenue Recognition - Schedule of Company's Total Revenues by Category for each Reportable Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue Recognition [Line Items]
Total	$ 938,955	$ 802,004
Building Materials Business
Revenue Recognition [Line Items]
Total	864,881	732,742
Products and Services
Revenue Recognition [Line Items]
Total	878,305	753,305
Products and Services | Building Materials Business
Revenue Recognition [Line Items]
Total	809,131	688,436
Freight
Revenue Recognition [Line Items]
Total	60,650	48,699
Freight | Building Materials Business
Revenue Recognition [Line Items]
Total	55,750	44,306
Operating Segments | Building Materials Business Mid-America Group
Revenue Recognition [Line Items]
Total	248,813	178,781
Operating Segments | Building Materials Business Southeast Group
Revenue Recognition [Line Items]
Total	119,237	80,239
Operating Segments | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	496,831	473,722
Operating Segments | Building Materials Business
Revenue Recognition [Line Items]
Total	864,881	732,742
Operating Segments | Magnesia Specialties
Revenue Recognition [Line Items]
Total	74,074	69,262
Operating Segments | Products and Services | Building Materials Business Mid-America Group
Revenue Recognition [Line Items]
Total	230,308	167,890
Operating Segments | Products and Services | Building Materials Business Southeast Group
Revenue Recognition [Line Items]
Total	115,312	77,563
Operating Segments | Products and Services | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	463,511	442,983
Operating Segments | Products and Services | Magnesia Specialties
Revenue Recognition [Line Items]
Total	69,174	64,869
Operating Segments | Freight | Building Materials Business Mid-America Group
Revenue Recognition [Line Items]
Total	18,505	10,891
Operating Segments | Freight | Building Materials Business Southeast Group
Revenue Recognition [Line Items]
Total	3,925	2,676
Operating Segments | Freight | Building Materials Business West Group
Revenue Recognition [Line Items]
Total	33,320	30,739
Operating Segments | Freight | Building Materials Business
Revenue Recognition [Line Items]
Total	55,750	44,306
Operating Segments | Freight | Magnesia Specialties
Revenue Recognition [Line Items]
Total	$ 4,900	$ 4,393