Stock-Based Compensation Programs - RSA and PCEQ activity (Details) - Restricted shares and restricted stock units	12 Months Ended
	Dec. 31, 2019 $ / shares shares
Stock-Based Compensation Programs
Vesting period	5 years
Restricted stock activity, Number of shares
Beginning of the period (in shares) | shares	2,875,294
Granted (in shares) | shares	543,384
Vested (in shares) | shares	(871,225)
Canceled/forfeited (in shares) | shares	(108,717)
End of the period (in shares) | shares	2,438,736
Restricted stock activity, Weighted average grant price
Beginning of the period (in dollars per share) | $ / shares	$ 34.17
Granted (in dollars per share) | $ / shares	45.88
Vested (in dollars per share) | $ / shares	30.83
Canceled/forfeited (in dollars per share) | $ / shares	39.68
End of the period (in dollars per share) | $ / shares	$ 37.73