Stock-Based Compensation, Stock Option Awards (Details) - Stock Options and Stock Appreciation Rights [Member] shares in Thousands	6 Months Ended
	Jun. 30, 2019 $ / shares shares
Shares [Roll Forward]
Outstanding, beginning balance (in shares) | shares	12,352
Granted (in shares) | shares	1,070
Exercised or settled (in shares) | shares	(3,890)
Forfeited (in shares) | shares	(90)
Expired (in shares) | shares	(9)
Outstanding, ending balance (in shares) | shares	9,433
Vested (in shares) | shares	7,266
Outstanding Weighted-Average Exercise Price [Abstract]
Outstanding, beginning balance (in dollars per share) | $ / shares	$ 10.93
Granted (in dollars per share) | $ / shares	27.05
Exercised or settled (in dollars per share) | $ / shares	8.72
Forfeited (in dollars per share) | $ / shares	30.42
Expired (in dollars per share) | $ / shares	32.06
Outstanding, ending balance (in dollars per share) | $ / shares	13.46
Vested (in dollars per share) | $ / shares	$ 9.61