Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity

The following table summarizes restricted stock activity for the years ended December 31, 2020, 2019, and 2018:

	Restricted Stock
	Number of Shares	Weighted Average Grant Date Fair Value
Outstanding at December 31, 2017	2,155,845	$	5.72
Granted	1,000,690	7.63
Vested	(1,277,076)	5.30
Canceled/Forfeited	(337,811)	6.51
Outstanding at December 31, 2018	1,541,648	$	7.14
Granted	1,586,590	4.90
Vested	(797,025)	6.36
Canceled/Forfeited	(146,538)	5.70
Outstanding at December 31, 2019	2,184,675	$	5.89
Granted	1,676,634	5.13
Vested	(928,778)	6.46
Canceled/Forfeited	(207,807)	5.36
Outstanding at December 31, 2020	2,724,724	$	5.26

Share-based Payment Arrangement, Performance Shares, Outstanding Activity

The following table summarizes performance shares activity for the years ended December 31, 2020, 2019, and 2018:

	Performance Shares
	Number of Shares	Weighted Average Grant Date Fair Value
Outstanding at December 31, 2017	2,368,281	$	4.44
Granted (1)	869,421	7.41
Vested	(1,086,058)	6.83
Canceled/Forfeited	(613,329)	5.41
Outstanding at December 31, 2018	1,538,315	$	4.05
Granted (2)	946,000	4.71
Vested	(969,903)	1.77
Canceled/Forfeited (2)	(300,267)	1.84
Outstanding at December 31, 2019	1,214,145	$	6.93
Granted (3)	1,343,953	3.95
Vested	(54,132)	11.47
Canceled/Forfeited (3)	(168,864)	10.71
Outstanding at December 31, 2020	2,335,102	$	4.83

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The following table sets forth the weighted average fair value of stock options and the assumptions used to estimate the fair value of the stock options using the Black-Scholes option valuation model:

	2020		2019		2018
Weighted average fair value of stock options granted	$	—	$	—	$	4.09
Volatility	—		—		66.86		%
Expected life in years	0		0		4.00
Risk-free interest rate	—		—		2.07		%
Dividend yield	—		—		—