Income Taxes (Rollforward of Valuation Allowances) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 132,928	$ 121,473	$ 114,962
Expenses	(60,835)	15,747	13,455
Deductions	(7,533)	(3,237)	(5,790)
Balance at End of Year	66,490	132,928	121,473
Valuation Allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	109,319	120,438	120,015
Expenses	4,547	9,277	6,589
Deductions	(9,998)	(1,040)	(2,668)
Effect of the 2017 Tax Act	(23,160)	(21,321)	0
State income tax, net of federal impact	(718)	956	536
Other activity (not resulting in expense or deduction)	624	1,009	(4,034)
Balance at End of Year	$ 80,614	$ 109,319	$ 120,438