Equity Incentive Program (Tables)

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement, Noncash Expense [Abstract]

Schedule of Black-Scholes Option-Pricing Assumptions

The expense related to stock options granted in the three months ended March 31, 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:


	Three Months Ended March 31,
	2020						2019
Risk-free interest rate	1.42%						2.44%
Dividend yield	—%						—%
Expected life (years)	4.3	to	4.5			4.5
Volatility	38.8%	to	40.6		%	42.9%

Fair value at date of grant	$5.56	to	$	5.95		$6.22

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 three months ended March 31, 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	—	—					886,799	16.77

Exercised	—	—					(14,475)	15.66
Forfeited	—	—					(59,306)	17.00
Expired	—	—					(9,379)	24.33
Outstanding at March 31, 2020	596,537	$	22.72	$	—	2.1	6,180,787	$	17.40	$	3.1	3.6

Exercisable at March 31, 2020	596,537	$	22.72	$	—	2.1	4,523,952	$	17.81	$	3.1	2.6

Schedule of Restricted Stock Units Award Activity

The following table summarizes the Company's restricted stock unit ("RSU") activity for the three months ended March 31, 2020:


	Share units	Weighted-average grant date fair value
Unvested at December 31, 2019	2,261,114	$	15.99
Granted	1,275,046	16.77

Vested ⁽¹⁾	(907,352)	16.24
Forfeited	(279,249)	15.99
Unvested at March 31, 2020	2,349,559	$	16.35

Share-based Payment Arrangement, Performance Shares, Outstanding Activity [Table Text Block]


	Share units	Weighted-average grant date fair value
Unvested at December 31, 2019	844,789	$	15.90
Granted	322,178	16.14

Vested ⁽¹⁾	(176,154)	15.38
Forfeited	(47,317)	15.85
Unvested at March 31, 2020	943,496	$	16.08