Stock-Based Compensation Performance Share Units Activity (Details)	3 Months Ended
	Mar. 31, 2016 $ / shares shares
PSU
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, shares, beginning of period | shares	106,964
Granted, shares | shares	34,728	[1]
Vested, shares | shares	(55,720)
Forfeited, shares | shares	(948)
Outstanding and nonvested, shares, end of period | shares	84,749
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding, weighted average fair value, beginning of period (usd per share) | $ / shares	$ 65.50
Granted, weighted average fair value (usd per share) | $ / shares	30.96	[1]
Vested, weighted average fair value (usd per share) | $ / shares	65.06
Forfeited, weighted average fair value (usd per share) | $ / shares	65.06
Outstanding and nonvested, weighted average fair value, end of period (usd per share) | $ / shares	$ 42.79
PSU Dividend Equivalent Unit (DEU) [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Granted, shares | shares	734
Dividend equivalent units vested, shares | shares	(1,009)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Granted, weighted average fair value (usd per share) | $ / shares	$ 36.19
Dividend equivalent units vested, weighted average fair value (usd per share) | $ / shares	$ 41.64

[1] Represents shares of PSUs for which performance targets have been established and which are deemed granted under U.S. GAAP.