Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments (Details 2)

v3.8.0.1
Financial Instruments (Details 2) - USD ($)
Mar. 31, 2018
Dec. 31, 2017
Mar. 31, 2017
Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Derivative Asset $ 2,118,000 $ 734,000 $ 0 $ 0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Derivative Financial Instruments, Assets [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Derivative Asset 0.000 0.000    
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Derivative Financial Instruments, Assets [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Derivative Asset 2,118,000.000 734,000.000    
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivative Financial Instruments, Assets [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Derivative Asset 0.000 0.000    
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Derivative Financial Instruments, Assets [Member]        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Derivative Asset $ 2,118,000.000 $ 734,000.000