Level 4 Debt (Details) (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Debt [Line Items]
Unamortized premium on 6.375% senior notes	$ 1,694,000		$ 0
Long-term debt	326,694,000		275,000,000
Interest paid	8,500,000	8,700,000
Asset-based revolving credit facility [Member]
Debt [Line Items]
Line of Credit Facility, Amount Outstanding	25,000,000		25,000,000
Original Senior Notes [Member]
Debt [Line Items]
6.375% senior notes, book value	250,000,000
6.375% senior notes [Member]
Debt [Line Items]
6.375% senior notes, book value	300,000,000		250,000,000
Interest rate	6.375%
Additional Senior Notes [Member]
Debt [Line Items]
6.375% senior notes, book value	$ 50,000,000
Premium rate on 6.375% senior notes	103.50%