Equity Awards - Summary of Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Shares
Granted (in shares)	0	0
Options
Shares
Beginning of year (in shares)	1,115,324	1,479,236	2,234,699
Granted (in shares)	0	0	205,244
Exercised (in shares)	(459,415)	(308,025)	(898,218)
Forfeited (in shares)	(12,058)	(55,887)	(62,489)
End of year (in shares)	643,851	1,115,324	1,479,236
Exercisable, end of year (in shares)	590,340	814,421	846,371
Weighted- Average Exercise Price
Beginning of year (in dollars per share)	$ 29.02	$ 27.81	$ 22.84
Granted (in dollars per share)	0	0	42.24
Exercised (in dollars per share)	26.87	22.01	18.53
Forfeited (in dollars per share)	36.84	35.69	30.80
End of year (in dollars per share)	30.41	29.02	27.81
Exercisable, end of year	$ 29.34	$ 26.46	$ 22.35