Equity Incentive Program (Tables)

9 Months Ended

Sep. 30, 2020

Share-based Payment Arrangement, Noncash Expense [Abstract]

Schedule of Black-Scholes Option-Pricing Assumptions

The expense related to stock options granted in the nine months ended September 30, 2020 and 2019 was estimated on the date of grant using a Black-Scholes option-pricing model based on the assumptions shown in the table below:

	Nine Months Ended September 30,
	2020			2019
Risk-free interest rate	0.11%	to	1.42%	1.72%	to	2.44%
Dividend yield	—%			—%
Expected life (years)	4.3	to	4.5	4.5
Volatility	38.8%	to	40.6%	41.0%	to	42.9%
Fair value at date of grant	$4.78	to	$5.95	$6.22	to	$7.35

Schedule of SSAR and Stock Options Activity

The following table summarizes the Company's stock-settled stock appreciation right ("SSAR") and stock option activity for the nine months ended September 30, 2020 (in millions, except share and per share amounts):

	SSARs						Stock Options
	Number of Shares	Weighted-Average Exercise Price		Aggregate Intrinsic Value		Weighted-Average Remaining Contractual Term (Years)	Number of Shares	Weighted-Average Exercise Price		Aggregate Intrinsic Value		Weighted-Average Remaining Contractual Term (Years)
Outstanding at December 31, 2019	596,537	$	22.72				5,377,148	$	17.51
Granted	—	—					896,875	16.75
Exercised	—	—					(129,463)	12.55
Forfeited	—	—					(173,680)	16.49
Expired	—	—					(138,742)	19.39
Outstanding at September 30, 2020	596,537	$	22.72	$	—	1.6	5,832,138	$	17.49	$	5.3	3.2
Exercisable at September 30, 2020	596,537	$	22.72	$	—	1.6	4,300,404	$	17.92	$	5.1	2.2

Schedule of Restricted Stock Units Award Activity

The following table summarizes the Company's restricted stock unit ("RSU") activity for the nine months ended September 30, 2020:

	Share units	Weighted-average grant date fair value
Unvested at December 31, 2019	2,261,114	$	15.99
Granted	1,431,843	16.50
Vested (1)	(1,040,850)	16.29
Forfeited	(715,701)	16.22
Unvested at September 30, 2020	1,936,406	$	16.16

(1) The number of RSUs vested includes shares that the Company withheld on behalf of employees to satisfy statutory tax withholding requirements.

Share-based Payment Arrangement, Performance Shares, Outstanding Activity

The following table summarizes the Company's PSU activity for the nine months ended September 30, 2020:

	Share units	Weighted-average grant date fair value
Unvested at December 31, 2019	844,789	$	15.90
Granted	322,178	16.14
Vested (1)	(184,405)	15.24
Forfeited	(61,589)	17.05
Unvested at September 30, 2020	920,973	$	16.04

(1) The number of PSUs vested includes shares that the Company withheld on behalf of employees to satisfy statutory tax withholding requirements.