Significant Accounting Policies Significant Accounting Policies (Write-down of Oil and Natural Gas Properties) (Details Textuals 3) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) $ / MMBTU $ / Barrel	Dec. 31, 2015 USD ($) $ / MMBTU $ / Barrel	Dec. 31, 2014 USD ($) $ / MMBTU $ / Barrel
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Ceiling test write-down | $	$ 810,921	$ 4,939,600	$ 0
Oil
Average Sales Price and Production Costs Per Unit of Production [Line Items]
average first-day-of-the-month NYMEX oil and natural gas price | $ / Barrel	42.75	50.28	94.99
Natural Gas
Average Sales Price and Production Costs Per Unit of Production [Line Items]
average first-day-of-the-month NYMEX oil and natural gas price | $ / MMBTU	2.55	2.63	4.30