Income Taxes - Tax Credit Carryforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Tax Credit Carryforward [Line Items]
Tax credits and other carryforwards, deferred tax benefit	$ 870	$ 640
Charitable Contributions [Member]
Tax Credit Carryforward [Line Items]
Tax credit carryforward	3,600
Tax credits and other carryforwards, deferred tax benefit	$ 700
Charitable Contributions [Member] | Minimum [Member]
Tax Credit Carryforward [Line Items]
Tax credit carryforward, expiration date	Dec. 31, 2019