Earnings Per Share - Schedule of Dilutive Effect of Stock Options RSUs and PSAs (Details) - shares	3 Months Ended									12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	[1]	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Basic weighted-average shares outstanding	18,646	18,666	18,775	18,972	18,988	18,965	19,008	18,994		18,766,000	18,989,000	19,335,000
Effect of potential exercise of stock options, RSUs, and performance shares										478,000	427,000	328,000
Diluted weighted-average shares outstanding	19,136	19,024	19,086	19,423	19,512	19,329	19,293	19,273		19,244,000	19,416,000	19,663,000

[1] Includes adjustments for the adoption ASU 2016-09 in the second quarter of 2016.