UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Shareholders' Equity
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, authorized	4,998,130	4,998,130
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, authorized	75,000,000	75,000,000
Common stock, issued	20,962,592	21,488,589
Common stock, outstanding	20,962,592	21,488,589
Series A Preferred Stock [Member]
Shareholders' Equity
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, authorized	5,000,000	5,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Series B Preferred Stock [Member]
Shareholders' Equity
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, authorized	1,870	1,870
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0