Related Party Transactions (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Related Party Transaction [Line Items]
Percentage of equity interest (in hundredths)	19.90%		19.90%
Amount of equity investment	$ 1,400,000	$ 1,500,000	$ 1,400,000	$ 1,500,000
Equity in earnings	211,000	192,000	543,000	551,000
Cash distribution from earnings of related party			400,000	1,000,000
Purchases from W&B	0	19,500,000	0	23,100,000
Maintenance and repair services, accessories and parts invoiced from related party	$ 300,000	$ 200,000	$ 1,200,000	$ 800,000