Benefit Plans - Changes in RSUs Outstanding (Details) - RSUs - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at beginning of year (in shares)	2,158,255	1,378,886	1,114,962
Acquired in business combination (in shares)	0	0	336,379
Granted (in shares)	2,030,026	1,412,941	509,725
Vested (in shares)	(879,085)	(500,204)	(503,879)
Forfeited (in shares)	(80,537)	(133,368)	(78,301)
Outstanding at end of year (in shares)	3,228,659	2,158,255	1,378,886