Stock Based Compensation Roll Forward Schedule of Stock Option Plan by Shares and Weighted Average Exercise Prices (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Roll Forward of Shares Outstanding [Roll Forward]
Outstanding, Beginning Balance, in shares	421,751
Granted, in shares	56,650	57,258	77,784
Exercised, in shares	(111,992)
Forfeited, in shares	(10,758)
Outstanding, Ending Balance, in shares	355,651	421,751
Exercisable at December 31, 2014, in shares	224,039
Vested and Expected to Vest, in shares	131,612
Roll Forward of Shares Outstanding - Weighted Average Exercise Price: [Roll Forward]
Outstanding, Beginning Balance, in Weighted Average Exercise Price,	$ 21.93
Granted, in Weighted Average Exercise Price	25.10
Exercised, in Weighted Average Exercise Price	21.47
Forfeited, in Weighted Average Exercise Price	23.97
Outstanding, Ending Balance, in Weighted Average Exercise Price,	22.52	$ 21.93
Exercisable at December 31, 2014, in Weighted Average Exercise Price	21.40
Vested and Expected to Vest, in Weighted Average Exercise Price	$ 24.44
Outstanding at December 31, 2014, Weighted Average Remaining Contractual Life, in years	5 years 7 months 1 day
Exercisable at December 31, 2014, Weighted Average Remaining Contractual Life, in years	4 years 20 days
Vested and Expected to Vest, Weighted Average Remaining Contractual Life, in years	8 years 2 months 14 days
Outstanding at December 31, 2014, Aggregate Intrinsic Value	$ 6,395
Exercisable at December 31, 2014, Aggregate Intrinsic Value	4,279
Vested and Expected to Vest, Aggregate Intrinsic Value	$ 2,116
Shares Available for Grant at Period End, in shares	367,775