Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Consolidated Balance Sheets
Accounts receivable - trade, allowance (in dollars)	$ 820	$ 623
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares issued	43,911,310	43,820,726
Common stock, shares outstanding	43,911,310	43,820,726