Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2019

Significant Accounting Policies [Line Items]

Changes in Accumulated Other Comprehensive Loss Net of Tax

Changes in accumulated other comprehensive loss, net of tax, are as follows:  

	(Dollars in Thousands)
	Pension and Postretirement Benefit Plans			Foreign Currency			Unamortized Value of Terminated Forward Starting Interest Rate Swap			Accumulated Other Comprehensive Loss
	Three Months Ended June 30, 2019
Balance at beginning of period	$	(138,747	)	$	(1,577	)	$	—		$	(140,324	)
Other comprehensive earnings before    reclassifications, net of tax		—			264			—			264
Amounts reclassified from accumulated    other comprehensive loss, net of tax		2,726			—			—			2,726
Other comprehensive earnings, net of tax		2,726			264			—			2,990
Balance at end of period	$	(136,021	)	$	(1,313	)	$	—		$	(137,334	)
	Three Months Ended June 30, 2018
Balance at beginning of period	$	(126,806	)	$	(609	)	$	(70	)	$	(127,485	)
Other comprehensive loss before    reclassifications, net of tax		—			(476	)		—			(476	)
Amounts reclassified from accumulated    other comprehensive loss, net of tax		2,008			—			70			2,078
Other comprehensive earnings (loss), net of tax		2,008			(476	)		70			1,602
Balance at end of period	$	(124,798	)	$	(1,085	)	$	—		$	(125,883	)
	Six Months Ended June 30, 2019
Balance at beginning of period	$	(141,505	)	$	(2,074	)	$	—		$	(143,579	)
Other comprehensive earnings before    reclassifications, net of tax		—			761			—			761
Amounts reclassified from accumulated    other comprehensive loss, net of tax		5,484			—			—			5,484
Other comprehensive earnings, net of tax		5,484			761			—			6,245
Balance at end of period	$	(136,021	)	$	(1,313	)	$	—		$	(137,334	)
	Six Months Ended June 30, 2018
Balance at beginning of period	$	(128,802	)	$	(22	)	$	(280	)	$	(129,104	)
Other comprehensive loss before    reclassifications, net of tax		—			(1,063	)		—			(1,063	)
Amounts reclassified from accumulated    other comprehensive loss, net of tax		4,004			—			280			4,284
Other comprehensive earnings (loss), net of tax		4,004			(1,063	)		280			3,221
Balance at end of period	$	(124,798	)	$	(1,085	)	$	—		$	(125,883	)

Noncurrent Deferred Tax Assets Recorded In Accumulated Other Comprehensive Loss

Changes in net noncurrent deferred tax assets recorded in accumulated other comprehensive loss are as follows:

	(Dollars in Thousands)
	Pension and Postretirement Benefit Plans			Unamortized Value of Terminated Forward Starting Interest Rate Swap			Net Noncurrent Deferred Tax Assets
	Three Months Ended June 30, 2019
Balance at beginning of period	$	83,339		$	—		$	83,339
Tax effect of other comprehensive earnings		(922	)		—			(922	)
Balance at end of period	$	82,417		$	—		$	82,417
	Three Months Ended June 30, 2018
Balance at beginning of period	$	79,280		$	41		$	79,321
Tax effect of other comprehensive earnings		(661	)		(41	)		(702	)
Balance at end of period	$	78,619		$	—		$	78,619
	Six Months Ended June 30, 2019
Balance at beginning of period	$	84,207		$	—		$	84,207
Tax effect of other comprehensive earnings		(1,790	)		—			(1,790	)
Balance at end of period	$	82,417		$	—		$	82,417
	Six Months Ended June 30, 2018
Balance at beginning of period	$	79,938		$	178		$	80,116
Tax effect of other comprehensive earnings		(1,319	)		(178	)		(1,497	)
Balance at end of period	$	78,619		$	—		$	78,619

Reclassification Out of Accumulated Other Comprehensive Loss

Reclassifications out of accumulated other comprehensive loss are as follows:

	Three Months Ended						Six Months Ended						Affected line items in the consolidated
	June 30,						June 30,						statements of earnings and
	2019			2018			2019			2018			comprehensive earnings
	(Dollars in Thousands)
Pension and postretirement benefit    plans
Amortization of:
Prior service credit	$	(184	)	$	(400	)	$	(396	)	$	(985	)
Actuarial loss		3,832			3,069			7,670			6,308
		3,648			2,669			7,274			5,323		Other nonoperating expense    and (income), net
Tax benefit		(922	)		(661	)		(1,790	)		(1,319	)	Income tax expense
	$	2,726		$	2,008		$	5,484		$	4,004
Unamortized value of terminated    forward starting interest rate swap
Additional interest expense	$	—		$	111		$	—		$	458		Interest expense
Tax benefit		—			(41	)		—			(178	)	Income tax expense
	$	—		$	70		$	—		$	280

Basic and Diluted Earnings Per Common Share

The following table reconciles the numerator and denominator for basic and diluted earnings per common share:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2019		2018		2019		2018
	(In Thousands)
Net earnings attributable to Martin Marietta    Materials, Inc.	$	189,475	$	185,377	$	232,328	$	195,400
Less: Distributed and undistributed earnings    attributable to unvested awards		400		317		491		378
Basic and diluted net earnings available to common    shareholders attributable to Martin Marietta    Materials, Inc.	$	189,075	$	185,060	$	231,837	$	195,022
Basic weighted-average common shares outstanding		62,563		63,021		62,574		62,989
Effect of dilutive employee and director awards		157		264		175		264
Diluted weighted-average common shares outstanding		62,720		63,285		62,749		63,253

Parent

Significant Accounting Policies [Line Items]

Comprehensive Earnings

Comprehensive earnings attributable to Martin Marietta is as follows:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2019		2018		2019		2018
	(Dollars in Thousands)
Net earnings attributable to Martin Marietta Materials, Inc.	$	189,475	$	185,377	$	232,328	$	195,400
Other comprehensive earnings, net of tax		2,990		1,602		6,245		3,221
Comprehensive earnings attributable to Martin Marietta    Materials, Inc.	$	192,465	$	186,979	$	238,573	$	198,621

Noncontrolling Interests

Significant Accounting Policies [Line Items]

Comprehensive Earnings

Comprehensive earnings attributable to noncontrolling interests, consisting of net earnings and adjustments for the funded status of pension and postretirement benefit plans, are as follows:

	Three Months Ended					Six Months Ended
	June 30,					June 30,
	2019			2018		2019			2018
	(Dollars in Thousands)
Net (loss) earnings attributable to noncontrolling interests	$	(6	)	$	126	$	(32	)	$	143
Other comprehensive earnings, net of tax		1			—		—			1
Comprehensive (loss) earnings attributable to    noncontrolling interests	$	(5	)	$	126	$	(32	)	$	144