Shareholders' Equity - Common Stock Outstanding (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock (in shares)	14,592,888	14,592,888
Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued, beginning balance (in shares)	71,675,379	66,033,509	65,891,930
Share issuances (in shares)	0	5,651,177	0
Issuance (repurchased) pursuant to benefit plans (in shares)	113,916	19,919	34,760
Restricted stock forfeited and withheld for taxes (in shares)	(70,672)	(51,049)	(126,682)
Exercised (in shares)	8,438	21,823	233,501
Shares issued, ending balance (in shares)	71,727,061	71,675,379	66,033,509
Treasury stock (in shares)	14,592,888	14,592,888	14,592,888
Total shares outstanding (in shares)	57,134,173	57,082,491	51,440,621
Class B
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued, beginning balance (in shares)	23,793,669	0
Share issuances (in shares)	0	23,793,669
Issuance (repurchased) pursuant to benefit plans (in shares)	0	0
Restricted stock forfeited and withheld for taxes (in shares)	0	0
Exercised (in shares)	0	0
Shares issued, ending balance (in shares)	23,793,669	23,793,669	0
Treasury stock (in shares)	0	0
Total shares outstanding (in shares)	23,793,669	23,793,669