Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Unrecognized tax benefits	$ 1,697	$ 1,632
Amounts of tax benefits that would affect effective tax rate if recognized	1,632	1,464
Income tax accrued interest	153	$ 139
Statute of limitations	$ 299