Joint Venture - Operating Results (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Goodwill	$ 12,973	$ 12,973	$ 69,289
Capital expenditures	8,250	12,351	11,604
Depreciation and amortization	24,854	26,044	26,188
Impairment of goodwill	0	56,160	0
Joint venture
Schedule of Equity Method Investments [Line Items]
Goodwill		3,525
Revenues	160,104	259,487	230,351
Net income (loss)	(2,876)	15,555	13,720
Current assets	66,645	93,679	82,827
Non-current assets	22,777	26,377	25,615
Current liabilities	7,792	11,896	10,548
Non-current liabilities	11,287	35,469	16,103
Members’ equity	70,343	72,691	81,791
Capital expenditures	2,176	3,042	1,789
Depreciation and amortization	2,390	$ 2,294	$ 2,217
Impairment of goodwill	$ 1,763