Stock-Based Compensation Plans - Information on Stock Options Outstanding (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest [Abstract]
Exercisable and vested options at period end, shares under option (in shares) | shares	4
Exercisable and vested options at period end, remaining contractual life (in years)	21 months
Exercisable and vested options at period end, average exercise price per share (in dollars per share)	$ 43.74
Exercisable and vested options at period end, intrinsic value per share (in dollars per share)	$ 106.71
Exercisable and vested options at period end, aggregate intrinsic value | $	$ 437
Common stock, market fair value (in dollars per share)	$ 150.45