Stock Based Compensation Roll Forward Schedule of Stock Option Plan by Shares and Weighted Average Exercise Prices (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) plan $ / shares shares	Dec. 31, 2017 $ / shares shares	Dec. 31, 2016 shares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Number of compensation plans | plan	3
Expiration period (in years)	10 years
Award vesting period (in years)	4 years
Shares Available for Grant at Period-End (in shares)		261,614
Roll Forward of Shares Outstanding [Roll Forward]
Outstanding, Beginning Balance, in shares	356,540
Granted, in shares	53,466	57,289.63	60,100.5
Exercised, in shares	(107,818)
Forfeited, in shares	(17,666)
Outstanding, Ending Balance, in shares	284,522	356,540
Exercisable, in shares	172,410
Vested and Expected to Vest, in shares	112,112
Roll Forward of Shares Outstanding - Weighted Average Exercise Price: [Roll Forward]
Outstanding, Beginning Balance, in Weighted Average Exercise Price, | $ / shares	$ 23.42
Granted, in Weighted Average Exercise Price | $ / shares	31.84
Exercised, in Weighted Average Exercise Price | $ / shares	20.92
Forfeited, in Weighted Average Exercise Price | $ / shares	27.06
Outstanding, Ending Balance, in Weighted Average Exercise Price, | $ / shares	25.67	$ 23.42
Exercisable, in Weighted Average Exercise Price | $ / shares	22.56
Vested and Expected to Vest, in Weighted Average Exercise Price | $ / shares	$ 30.46
Outstanding, Weighted Average Remaining Contractual Life, in years	5 years 5 months 9 days
Exercisable, Weighted Average Remaining Contractual Life, in years	3 years 8 months 5 days
Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term	8 years 1 month 28 days
Outstanding, Aggregate Intrinsic Value | $	$ 1,807
Exercisable, Aggregate Intrinsic Value | $	1,631
Vested and Expected to Vest, Aggregate Intrinsic Value | $	$ 176