Quarterly report pursuant to Section 13 or 15(d)

Related Party Transactions (Details)

v3.7.0.1
Related Party Transactions (Details) - USD ($)
1 Months Ended 6 Months Ended 12 Months Ended
Jul. 11, 2016
Jan. 31, 2001
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2001
Apr. 30, 2008
Dec. 31, 1991
Related Party Transaction [Line Items]              
Shares repurchased value     $ 5,633,000 $ 20,532,000      
Common Stock - Class A [Member]              
Related Party Transaction [Line Items]              
Shares repurchased value     $ 7,000 $ 196,000      
Investor [Member] | Common Stock - Class A [Member]              
Related Party Transaction [Line Items]              
Shares repurchased 1,000,000            
Shares repurchased value $ 16,100,000            
Immediate Family Member of Management or Principal Owner [Member] | Property [Member]              
Related Party Transaction [Line Items]              
Capital lease obligations           $ 1,300,000 $ 900,000
Chief Executive Officer [Member] | Air Transportation Equipment Two [Member]              
Related Party Transaction [Line Items]              
Termination period on lease   12 months          
Monthly lease payment   $ 132,000          
Security deposit         $ 1,500,000    
Security deposit termination period         6 months