Investments in Partnerships and LLCs (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	6 Months Ended	12 Months Ended									6 Months Ended
	Jan. 31, 2012	Jun. 30, 2013	Dec. 31, 2009 agreement company	Dec. 31, 2012	Jun. 30, 2013 EM 646 [Member]	Jun. 30, 2013 EM 646 [Member] Minimum [Member]	Jun. 30, 2013 EM 646 [Member] Maximum [Member]	Jun. 30, 2013 Unconsolidated Variable Interest Entities [Member] Minimum [Member]	Jun. 30, 2013 Unconsolidated Variable Interest Entities [Member] Maximum [Member]	Jun. 30, 2013 Variable Interest Entity, Primary Beneficiary [Member]	Dec. 31, 2012 Variable Interest Entity, Primary Beneficiary [Member]	Jun. 30, 2013 Variable Interest Entity, Not Primary Beneficiary [Member]	Jun. 30, 2012 Variable Interest Entity, Not Primary Beneficiary [Member]
Noncontrolling Interest [Line Items]
Ownership percentage (percent)		60.00%				20.00%		20.00%	50.00%
Noncontrolling Interest, Ownership Percentage by Parent					58.20%		58.20%
Number of separate agreements with unrelated third parties (agreements)			2
Number of limited liabilities formed (companies)			2
Real estate inventory		$ 188,086		$ 171,044						$ 33,267	$ 32,659
Gain on sale of property	2,731
Gain recognized in consolidated statement of operations		1,639
Contributions to unconsolidated entities												$ 94	$ 66