Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011
Statement of Financial Position [Abstract]
Trade and other accounts receivable, allowance	$ 157	$ 341	$ 216	$ 281	$ 450	$ 451	$ 353	$ 209
Common stock, par value	$ 0.10	$ 0.10	$ 0.10	$ 0.10	$ 0.1000	$ 0.10	$ 0.10	$ 0.10
Common stock, shares authorized	40,000,000	40,000,000	40,000,000	40,000,000	40,000,000	40,000,000	40,000,000	40,000,000
Common stock, shares issued	29,162,000	29,183,000	29,136,000	29,127,000	28,174,000	28,123,000	27,955,000	27,950,000
Common stock, shares outstanding	29,162,000	29,183,000	29,136,000	29,127,000	28,174,000	28,123,000	27,955,000	27,950,000