Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Consolidated Balance Sheets
Accounts receivable - trade, allowance (in dollars)	$ 623	$ 1,021
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	43,820,726	43,479,186
Common stock, shares outstanding	43,820,726	43,479,186