Unconsolidated Joint Ventures - Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Equity Method Investments and Joint Ventures [Abstract]
Revenues	$ 70,104	$ 58,186	$ 112,061	$ 139,410
Cost of sales	53,860	45,486	89,764	109,284
Gross margin	16,244	12,700	22,297	30,126
Operating expenses	6,049	5,063	9,961	11,723
Net income of unconsolidated joint ventures	10,195	7,637	12,336	18,403
Equity in net income of unconsolidated joint ventures reflected in the accompanying condensed consolidated statements of operations	$ 3,947	$ 3,256	$ 3,940	$ 5,124