Consolidated Statements of Shareholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Issuance of common stock tax benefits	$ 0	$ 0	$ 0
Cash dividends	$ 0.09	$ 0.36	$ 0.72
Common Stock [Member]
Issuance of common stock tax benefits	$ 0	$ 0	$ 0
Additional Paid-in Capital [Member]
Issuance of common stock tax benefits	$ 0	0	$ 0
Retained Earnings [Member]
Issuance of common stock tax benefits		$ 0
Cash dividends	$ 0.09	$ 0.36	$ 0.72