Notes Payable (Interest Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Debt Disclosure [Abstract]
Total interest incurred	$ 25,570	$ 28,384	$ 37,180
Interest capitalized	(1,637)	(600)	0
Total interest expense	$ 23,933	$ 27,784	$ 37,180