Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2020

Accounting Policies [Abstract]

Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block]

The following table presents the number of awards outstanding for each award type as of December 31, 2020 and 2019 (in thousands): 

	Year Ended December 31,
Award type	2020	2019
Restricted stock units (time-based)	1,802	1,893
Restricted stock units (performance-based)	162	114
Stock appreciation rights	28	65
Market stock units	111	267