Employee Benefit Plans (Schedule of Stock Option Activity) (Details) - Stock Options shares in Thousands	9 Months Ended
	Sep. 30, 2018 $ / shares shares
Number of shares
Beginning balance (in shares) | shares	1,879
Granted (in shares) | shares	378
Exercised (in shares) | shares	(226)
Expired (in shares) | shares	(6)
Ending balance (in shares) | shares	2,025
Weighted Average Exercise Price Per Share
Beginning balance (in dollars per share) | $ / shares	$ 34.08
Granted (in dollars per share) | $ / shares	69.70
Exercised (in dollars per share) | $ / shares	23.02
Expired (in dollars per share) | $ / shares	21.45
Ending balance (in dollars per share) | $ / shares	$ 42.00