Significant Accounting Policies (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended
	Sep. 30, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accounting Policies [Abstract]
LIFO inventory as a percent of total inventory		30.60%	31.30%
Excess of FIFO cost over LIFO		$ 15,000,000	$ 15,700,000
Share-based compensation expense		3,321,000	5,016,000	3,496,000
Non-cash compensation charges	$ 1,700,000
Stock reissued from treasury related to exercise of warrants, shares		0	0	2,599,769
Stock reissued from treasury related to exercise of warrants, average cost per share				$ 27.04