Income Taxes (Tax Return Reported Federal Net Operating Losses and Tax Credits) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Federal [Member]
Net operating losses	$ 781,019
Net operating losses carried forward, expiration date	Dec. 31, 2036
Foreign [Member]
Net operating losses	$ 40,957
Research Tax Credit [Member]
Tax credit	$ 23,166
Net operating losses carried forward, expiration date	Dec. 31, 2036
Alternative Minimum Tax [Member]
Tax credit	$ 94