Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Loss Contingencies [Line Items]
Guaranteed Repayment of Economic Development Bonds	$ 52,400,000
Number of unconsolidated subsidiaries for which loans guaranteed	2
Maximum Guarantee Exposure for Joint Venture Loans	155,000,000
Total obligation for operating leases for certain land positions	271,800,000
Other Liabilities	96,866,000	142,589,000
Special Tax Assessment [Member]
Loss Contingencies [Line Items]
Other Liabilities	$ 12,300,000