Employee Benefit Plan Employee Benefit Plan (Details) $ in Thousands		12 Months Ended
	Jul. 31, 2016	Dec. 31, 2017 USD ($) employee	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Vesting percentage of employer contribution	100.00%
Costs recognized		$ 243	$ 142	$ 96
Number of participants | employee		291
Deferred Compensation Arrangement with Individual, Percent of Base Salary That May Be Deferred			50.00%
Deferred Compensation Arrangement with Individual, Percent of Bonus That May Be Deferred			100.00%
Deferred Compensation Arrangement with Individual, Plan Assets		$ 11
Deferred Compensation, Period 1 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred Compensation Arrangement with Individual, Maximum Contractual Term			5 years
Deferred Compensation, Period 2 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred Compensation Arrangement with Individual, Maximum Contractual Term			10 years
Deferred Compensation, Period 3 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Deferred Compensation Arrangement with Individual, Maximum Contractual Term			15 years
Range one
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contribution, percent match on employee contribution	50.00%
Range two | Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer matching contribution on salary of employee	4.00%