Shareholders' Equity Total compensation cost related to nonvested awards (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock Issued During Period, Shares, Restricted Stock Award, Gross	126,849	92,800
weighted average estimated fair value of restricted stock	$ 5.50	$ 26.82
Stock Issued During Period, Value, Restricted Stock Award, Gross	$ 698,100	$ 2,488,600
Restricted Stock [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized compensation cost	$ 382,300
Excepted weighted-average period in years of compensation cost to be recognized	1 year 9 months 4 days
Stock Option [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Unrecognized compensation cost	$ 1,245,500
Excepted weighted-average period in years of compensation cost to be recognized	1 year 9 months 18 days