Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Share-based compensation disclosures

Stock option transactions under various stock-based employee compensation plans

				Weighted-
		Weighted-		Average
		Average		Remaining		Aggregate
		Exercise		Contractual		Intrinsic
Options	Shares	Price		Term		Value
	(In thousands, except exercise price)
Options outstanding as of December 31, 2017	4,394	$	13.04
Granted	171		4.82
Exercised	—		—
Forfeited	(789)		19.28
Options outstanding as of December 31, 2018	3,776	$	11.36	2.03	years	$	—
Options exercisable as of December 31, 2018	3,759	$	11.35	2.01	years	$	—

Schedule of grant date fair value

	Year Ended December 31,
	2018		2017		2016
Weighted average fair value of options granted	$	1.75	$	2.86	$	3.52
Weighted average risk free interest rate		2.59%		1.85%		1.09%
Dividend yield		3.03%		2.94%		2.21%
Volatility (1)		57.11%		50.82%		45.69%
Expected life (in years)		4.0		4.0		4.0

(1) Expected volatilities are based on implied volatilities from publicly traded options to purchase Nabors' common shares, historical volatility of Nabors' common shares and other factors.

Unvested stock options

		Weighted-Average
		Grant-Date Fair
Unvested Stock Options	Outstanding	Value
	(In thousands, except fair value)
Unvested as of December 31, 2017	34	$	5.21
Granted	171		1.75
Vested	(188)		2.07
Forfeited	—		—
Unvested as of December 31, 2018	17	$	5.21

Restricted Shares Award

Share-based compensation disclosures

Unvested restricted stock

		Weighted-Average
		Grant-Date Fair
Restricted shares	Outstanding	Value
	(In thousands, except fair value)
Unvested as of December 31, 2017	3,298	$	12.67
Granted	2,392		6.92
Vested	(1,290)		13.32
Forfeited	(788)		10.25
Unvested as of December 31, 2018	3,612	$	9.16

Restricted Stock Based on Performance Conditions

Share-based compensation disclosures

Unvested restricted stock

		Weighted-Average
		Grant-Date Fair
Performance based restricted shares	Outstanding	Value
	(In thousands, except fair value)
Outstanding as of December 31, 2017	1,413	$	12.49
Granted	1,010		6.89
Vested	(677)		12.24
Outstanding as of December 31, 2018	1,746	$	9.35

Restricted Stock Based on Market Conditions

Share-based compensation disclosures

Schedule of grant date fair value

		Year Ended December 31,
	2018		2017		2016
Risk free interest rate		2.02%		1.62%		1.41%
Expected volatility		57.00%		55.00%		52.00%
Closing stock price at grant date	$	6.87	$	16.81	$	8.64
Expected term (in years)		3.0		3.0		3.0

Unvested restricted stock

		Weighted-Average
		Grant-Date Fair
Market based restricted shares	Outstanding	Value
	(In thousands, except fair value)
Outstanding as of December 31, 2017	1,692	$	7.89
Granted	1,058		4.77
Vested	(218)		8.67
Forfeited	(1,175)		5.86
Outstanding as of December 31, 2018	1,357	$	7.09