Income Taxes (Other Unrecognized Tax Benefits Disclosures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate	$ 4,107	$ 3,414	$ 378
Interest, net of tax benefit, accrued in the Consolidated Balance Sheets	572	92	28
Penalties, accrued in the Consolidated Balance Sheets	38	181	0
Interest expense (benefit) recognized in the Consolidated Statements of Operations	506	64	(146)
Interest expense (benefit) recognized in the Consolidated Statements of Operations	(67)	$ 181	$ 0
Reasonably possible decrease in gross unrecognized tax benefits, within 12 months	$ 3,600