Indebtedness Indebtedness (Schedule of Maturities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Long-term Debt, Current Maturities	$ 75,170
2017	293,379
2018	275,374
2019	432,041
2020	262,463
Thereafter	1,592,789
Long-term Debt	2,931,216
Interest Paid, Net	163,400	$ 211,800	$ 229,000
Interest Paid, Capitalized	$ 16,100	$ 16,800	$ 17,600