Notes Payable (Interest Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Disclosure [Abstract]
Total interest incurred	$ 31,347	$ 26,314	$ 23,735
Interest capitalized	(4,697)	(3,579)	(2,752)
Total interest expense	$ 26,650	$ 22,735	$ 20,983