Stock-based Compensation - Schedule of Stock Options Outstanding (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Summary of stock options outstanding and related information
Number of options outstanding at beginning of period | shares	9,737
Number of options granted | shares	0
Number of options exercised | shares	(873)
Number of options forfeited | shares	(124)
Number of options expired | shares	(138)
Number of options outstanding at end of period | shares	8,602
Weighted average exercise price per option outstanding at beginning of period | $ / shares	$ 53.80
Weighted average exercise price per option granted | $ / shares	0.00
Weighted average exercise price per option exercised | $ / shares	44.25
Weighted average exercise price per option forfeited | $ / shares	53.90
Weighted average exercise price per option expired | $ / shares	67.85
Weighted average exercise price per option outstanding at end of period | $ / shares	$ 54.56
Options additional disclosure
Number of options exercisable at the end of the period | shares	7,363
Weighted average exercise price per option exercisable at the end of period | $ / shares	$ 54.46