Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Option Plans Activity

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

	2019					2018					2017
				Weighted-					Weighted-					Weighted-
				Average					Average					Average
				Exercise					Exercise					Exercise
Year Ended December 31,	Shares			Price		Shares			Price		Shares			Price
Number of shares under stock options:
Outstanding at beginning of year		3,828		$	49.71		4,106		$	47.96		3,591		$	45.32
Granted		489		$	48.00		265		$	65.80		698		$	59.07
Exercised		(425	)	$	37.97		(543	)	$	44.33		(183	)	$	38.56
Canceled		—			—		—			—		—			—
Outstanding at end of year		3,892		$	50.78		3,828		$	49.71		4,106		$	47.96
Stock options exercisable at end of year		3,276		$	49.79		2,112		$	45.41		1,809		$	43.39

Summary of Stock Options Outstanding

The following table summarizes information about stock options outstanding at December 31, 2019 (shares in thousands):

	Options Outstanding					Options Exercisable
			Weighted-
			Average	Weighted-				Weighted-
Range of	Number		Remaining Contractual	Average Exercise		Number		Average Exercise
Exercise Prices	Outstanding		Life	Price		Exercisable		Price
$35.00 - $45.00		576	2.9 years	$	42.65		576	$	42.65
$45.01 - $55.00		2,352	6.0 years	$	48.61		2,122	$	48.68
$55.01 - $65.00		698	6.9 years	$	59.07		412	$	59.07
$65.01 - $75.00		266	7.9 years	$	65.80		166	$	65.80
$35.00 - $75.00		3,892	5.8 years	$	50.78		3,276	$	49.79

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:

	2019	2018	2017
Exercise price	$48.00	$65.80	$59.07
Expected dividend yield	3.33%	2.31%	2.56%
Expected stock price volatility	25.57%	25.28%	26.53%
Risk-free interest rate	2.03%	2.85%	2.02%
Expected life (in years)	6.5	6.5	6.5

Summary of Nucor's RSU Activity

The fair value of an RSU is determined based on the closing price of Nucor’s common stock on the date of the grant.

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

	2019					2018					2017
				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		1,246		$	59.09		1,071		$	52.62		1,040		$	48.47
Granted		1,770		$	48.00		1,013		$	65.80		721		$	59.07
Vested		(1,207	)	$	52.43		(827	)	$	58.98		(677	)	$	53.17
Canceled		(33	)	$	57.09		(11	)	$	55.02		(13	)	$	50.21
Unvested at end of year		1,776		$	52.60		1,246		$	59.09		1,071		$	52.62

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):

	2019					2018					2017
				Grant Date					Grant Date					Grant Date
Year Ended December 31,	Shares			Fair Value		Shares			Fair Value		Shares			Fair Value
Restricted stock units and restricted stock awards:
Unvested at beginning of year		130		$	62.97		91		$	54.50		67		$	45.77
Granted		316		$	58.04		256		$	67.68		172		$	60.62
Vested		(299	)	$	58.82		(217	)	$	64.95		(148	)	$	51.72
Canceled		—		$	—		—		$	—		—		$	—
Unvested at end of year		147		$	60.81		130		$	62.97		91		$	54.50