Income Taxes - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Finalized Tax Benefit Related to Deferred Tax Balances Previously Recorded Related to Tax Cuts and Jobs Act	$ 9,157
Final Tax Benefit for One Time Transition Tax Related to Tax Cuts and Jobs Act	1,779
Unrecognized tax benefits	2,674	$ 2,318
Accrued interest and penalties	$ 1,104	$ 983