Commitments and Contingencies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) entities	Dec. 31, 2017 USD ($)
Loss Contingencies [Line Items]
Guaranteed Repayment of Economic Development Bonds	$ 23,700
Number of unconsolidated subsidiaries for which loans guaranteed | entities	1
Maximum Guarantee Exposure for Joint Venture Loans	$ 122,200
Other Liabilities	205,433	$ 210,825
Special Tax Assessment [Member]
Loss Contingencies [Line Items]
Other Liabilities	10,900
Land [Member]
Loss Contingencies [Line Items]
Total obligation for operating leases	92,000
Office [Member]
Loss Contingencies [Line Items]
Total obligation for operating leases	$ 32,000