Acquisition of Guilford Builders Supply (Narrative) (Details) - USD ($)	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 7,186,000	$ 7,186,000
GBS [Member]
Business Acquisition [Line Items]
Date of acquisition	Jun. 01, 2015
Acquisition purchase price, including holdback	$ 2,200,000
Initial holdback amount	200,000
Goodwill	0
GBS [Member] | Selling, general and administrative expenses [Member]
Business Acquisition [Line Items]
Acquisition costs	$ 100,000