Other Assets (Textual) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Noncash project abandonment costs	$ 0	$ 937,000	$ 829,000
Net amortization expense of intangible assets and liabilities	$ 3,300,000	$ 305,000	$ 4,000