CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Shareholders' equity
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	21,369,885	21,111,585
Common stock, shares outstanding (in shares)	21,369,885	21,111,585