Annual report pursuant to Section 13 and 15(d)

Schedule of Equity Method Investment, Financial Information, Statement of Operations (Details)

v3.7.0.1
Schedule of Equity Method Investment, Financial Information, Statement of Operations (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]      
Cumulative unfunded net losses of equity investees $ 1,100 $ 100  
Dart Holding Company Ltd.      
Schedule of Equity Method Investments [Line Items]      
Operating revenues 40,930 33,190 $ 40,174
Operating and administrative 32,878 32,869 31,755
Depreciation and amortization 3,161 4,224 4,129
Total Costs and Expenses 36,039 37,093 35,884
Operating income 4,891 (3,903) 4,290
Net income 2,657 (3,150) 2,172
Other Investments      
Schedule of Equity Method Investments [Line Items]      
Operating revenues 694 622 2,737
Operating and administrative 338 685 750
Depreciation and amortization 519 740 2,370
Total Costs and Expenses 857 1,425 3,120
Operating income (163) (803) (383)
Net income $ (409) $ (1,064) $ (749)