Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Concentration of Credit Risk
Expense for bad debts	$ 1,098,000	$ (543,000)	$ 915,000
Inventories
Percentage of LIFO Inventory	20.00%
Cost valuation of inventory if FIFO had been used exclusively	8,100,000	8,700,000	9,600,000
Liquidation of LIFO inventories decreased cost of sales and increased income before taxes	100,000	400,000	800,000
Long-Lived Assets
Impairment charges	0	0	1,249,000
Shipping and Handling
Shipping and handling expenses	32,400,000	32,200,000	26,600,000
Cash and Cash Equivalents
Accrued capital expenditures excluded from investing activities	500,000	400,000	1,800,000
Canada [Member] | Sales [Member]
Concentration of Credit Risk
Concentration risk percentage	8.00%	9.00%	9.00%
Canada [Member] | Sales [Member] | Customer Concentration Risk [Member]
Concentration of Credit Risk
Concentration risk percentage	8.00%
Senior Notes [Member] | Carrying Value [Member]
Fair Value Measurement
Senior Notes	11,000,000
Senior Notes [Member] | Fair Value [Member]
Fair Value Measurement
Senior Notes	$ 10,800,000
Customer 1 [Member] | Sales [Member] | Customer Concentration Risk [Member]
Concentration of Credit Risk
Concentration risk percentage	4.00%
Minimum [Member] | Customer 2 [Member] | Sales [Member] | Customer Concentration Risk [Member]
Concentration of Credit Risk
Concentration risk percentage	3.00%