Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Activity related to unrecognized tax benefits
Beginning Balance	$ 10,419	$ 7,125
Additions for tax positions related to prior years	0	5,819
Settlements with taxing authorities	0	(2,525)
Ending Balance	10,419	10,419	$ 7,125
Total amount of unrecognized tax benefits that, if recognized, would impact the effective tax rate	8,200	6,800
Interest and penalties related to income taxes	450	6,200	$ (460)
Total interest and penalties accrued	$ 8,400	$ 7,900