Discontinued Operations (Details) (USD $)	0 Months Ended	12 Months Ended
	Nov. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Discontinued operations [Abstract]
Income (loss) from operations		$ 3,401,000	$ 225,000	$ (1,269,000)
Gain on sale of subsidiary [Abstract]
Gain on sale of subsidiary		3,378,000	0	0
Income (loss) from discontinued operations		6,779,000	225,000	(1,269,000)
American Augers, Inc. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of Augers	42,940,000
Post closing adjustment		288,000
Discontinued operation, summarized financial information [Abstract]
Revenues		53,619,000	47,088,000	34,251,000
Discontinued operations [Abstract]
Operating income (loss) before tax		5,218,000	169,000	(1,787,000)
Income tax provision (benefit)		1,817,000	(56,000)	(518,000)
Income (loss) from operations		3,401,000	225,000	(1,269,000)
Gain on sale of subsidiary [Abstract]
Gain on sale of subisidiary before tax		5,357,000	0	0
Income tax provision		1,979,000	0	0
Gain on sale of subsidiary		3,378,000	0	0
Income (loss) from discontinued operations		6,779,000	225,000	(1,269,000)
Assets [Abstract]
Cash	636,000
Receivables	5,334,000
Inventories	26,568,000
Prepaid and other assets	430,000
Property and equipment, net	13,500,000
Other assets	465,000
Total assets	46,933,000
Liabilities [Abstract]
Accounts payable	2,518,000
Other liabilities	6,484,000
Total liabilities	9,002,000
Net assets disposed	$ 37,931,000