Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Stock Option Plans Activity

A summary of activity under Nucor’s stock option plans is as follows (shares in thousands):

	2018					2017					2016
Year Ended December 31,	Shares			Weighted - Average Exercise Price		Shares			Weighted - Average Exercise Price		Shares			Weighted - Average Exercise Price
Number of shares under option:
Outstanding at beginning of year		4,106		$	47.96		3,591		$	45.32		3,092		$	43.51
Granted		265		$	65.80		698		$	59.07		899		$	48.80
Exercised		(543	)	$	44.33		(183	)	$	38.56		(400	)	$	39.19
Canceled		—			—		—			—		—			—
Outstanding at end of year		3,828		$	49.71		4,106		$	47.96		3,591		$	45.32
Options exercisable at end of year		2,112		$	45.41		1,809		$	43.39		1,557		$	40.80

Summary of Stock Options Outstanding

The following table summarizes information about stock options outstanding at December 31, 2018 (shares in thousands):

	Options Outstanding						Options Exercisable
Range of Exercise Prices	Number Outstanding		Weighted- Average Remaining Contractual Life		Weighted- Average Exercise Price		Number Exercisable		Weighted- Average Exercise Price
$35.00 - $45.00		967		3.7 years	$	40.31		967	$	40.31
45.01 - 55.00		1,897		6.7 years	$	48.81		1,064	$	48.81
55.01 - 65.00		698		8.4 years	$	59.07		48	$	59.07
65.01 - 75.00		266		9.4 years	$	65.80		33	$	65.80
$35.00 - $75.00		3,828		6.4 years	$	49.71		2,112	$	45.41

Schedule of Grant Date Fair Value Black-Scholes Option-Pricing Model Assumptions

The fair value was estimated using the Black-Scholes option-pricing model with the following assumptions:

	2018			2017			2016
Exercise price	$	65.80		$	59.07		$	48.80
Expected dividend yield		2.31	%		2.56	%		3.07	%
Expected stock price volatility		25.28	%		26.53	%		26.14	%
Risk-free interest rate		2.85	%		2.02	%		1.67	%
Expected life (in years)		6.5			6.5			6.5

Summary of Nucor's RSU Activity

A summary of Nucor’s RSU activity is as follows (shares in thousands):

	2018					2017					2016
				Grant Date					Grant Date					Grant Date
Year Ended December 31,	Shares			Fair Value		Shares			Fair Value		Shares			Fair Value
Restricted stock units:
Unvested at beginning of year		1,071		$	52.62		1,040		$	48.47		1,031		$	47.93
Granted		1,013		$	65.80		721		$	59.07		723		$	48.80
Vested		(827	)	$	58.98		(677	)	$	53.17		(681	)	$	48.09
Canceled		(11	)	$	55.02		(13	)	$	50.21		(33	)	$	46.44
Unvested at end of year		1,246		$	59.09		1,071		$	52.62		1,040		$	48.47

Summary of Nucor's Restricted Stock Activity under AIP and LTIP

A summary of Nucor’s restricted stock activity under the AIP and the LTIP is as follows (shares in thousands):

	2018					2017					2016
				Grant Date					Grant Date					Grant Date
Year Ended December 31,	Shares			Fair Value		Shares			Fair Value		Shares			Fair Value
Restricted stock awards and units:
Unvested at beginning of year		91		$	54.50		67		$	45.77		63		$	48.07
Granted		256		$	67.68		172		$	60.62		123		$	44.03
Vested		(217	)	$	64.95		(148	)	$	51.72		(116	)	$	45.16
Canceled		—			—		—			—		(3	)	$	45.75
Unvested at end of year		130		$	62.97		91		$	54.50		67		$	45.77