Bluegrass Acquisition - Additional Information (Detail) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Combinations [Line Items]
Business acquisition in cash					$ 1,645,698,000
Total Revenues		$ 1,279,468,000	$ 1,202,403,000	$ 2,218,423,000	2,004,407,000
Earnings (Loss) from operations		285,882,000	263,953,000	355,103,000	303,034,000
Bluegrass Materials Company
Business Combinations [Line Items]
Business acquisition in cash	$ 1,620,000,000
Total Revenues		70,169,000	46,111,000	116,633,000	46,111,000
Earnings (Loss) from operations		$ 23,628,000	$ 6,611,000	$ 28,307,000	$ 6,611,000