Stock-Based Compensation Performance Share Units Activity (Details)	3 Months Ended
	Mar. 31, 2018 $ / 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) | shares	252,815
Granted (shares) | shares	54,059	[1]
Vested (shares) | shares	(36,920)
Forfeited (shares) | shares	(139,628)
Outstanding and nonvested, shares, end of period (shares) | shares	128,441
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	$ 22.53
Granted, weighted average fair value (usd per share) | $ / shares	42.40	[1]
Vested, weighted average fair value (usd per share) | $ / shares	38.67
Forfeited, weighted average fair value (usd per share) | $ / shares	13.25
Outstanding and nonvested, weighted average fair value, end of period (usd per share) | $ / shares	$ 36.58
PSU Dividend Equivalent Unit (DEU)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Granted (shares) | shares	1,026
Vested (shares) | shares	(2,680)
Forfeited (shares) | shares	(231)
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	$ 40.71
Vested, weighted average fair value (usd per share) | $ / shares	35.20
Forfeited, weighted average fair value (usd per share) | $ / shares	$ 35.24

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