Summary of Significant Accounting Policies (Reclassification Adjustments) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Personal Property	$ 9,168	$ 8,739
Accumulated depreciation	613,882	580,617
Other assets, net	151,194	126,962
Reclassification
Personal Property	(23,300)	(10,400)
Accumulated depreciation	(6,800)	(6,100)
Other assets, net	$ 16,500	$ 4,300