Investments in Unconsolidated Entities Summarized Financial Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]
Revenues	$ 87,033	$ 72,393	$ 44,015
Operating income	12,428	9,878	1,196
Income from continuing operations	6,397	4,603	(2,382)
Net income (loss)	5,197	4,598	$ (2,382)
Equity Method Investment, Summarized Financial Information, Assets [Abstract]
Current assets	56,599	47,294
Non-current assets	491,388	346,550
Total assets	547,987	393,844
Equity Method Investment, Summarized Financial Information, Liabilities [Abstract]
Current liabilities	31,191	22,274
Non-current liabilities	222,156	143,769
Total liabilities	$ 253,347	$ 166,043