Debt (Schedule of Long-Term Debt) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Long-term debt, Including current installments on long-term debt	$ 357,576,000	$ 366,403,000
Timberland Acquisitions	2
Number of Tranches Included in Term Loan	2
Term Loan Tranche	6,000,000
Less current installments on long-term debt	8,413,000	21,661,000
Long-term debt	349,163,000	344,742,000
Revenue bonds, fixed rate 5.9% to 7.75%, due 2014 through 2026 [Member]
Debt Instrument [Line Items]
Repayments of Other Long-term Debt	5,200,000
Long-term debt, Including current installments on long-term debt	144,627,000	149,745,000
Revenue bonds, fixed rate 5.9% to 7.75%, due 2014 through 2026 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest Rate	5.90%
Revenue bonds, fixed rate 5.9% to 7.75%, due 2014 through 2026 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest Rate	7.75%
7.5% Senior Notes, due 2019 [Member]
Debt Instrument [Line Items]
Long-term debt, Including current installments on long-term debt	148,241,000	147,984,000
Interest Rate	7.50%
Debentures, 6.95%, due 2015 [Member]
Debt Instrument [Line Items]
Long-term debt, Including current installments on long-term debt	22,493,000	22,490,000
Interest Rate	6.95%
Medium-term notes, fixed rate 8.75% to 8.89%, due 2016 through 2022 [Member]
Debt Instrument [Line Items]
Repayments of Medium-term Notes	16,500,000	5,000,000
Long-term debt, Including current installments on long-term debt	27,250,000	43,750,000
Medium-term notes, fixed rate 8.75% to 8.89%, due 2016 through 2022 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest Rate	8.75%
Medium-term notes, fixed rate 8.75% to 8.89%, due 2016 through 2022 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest Rate	8.89%
Term Loans, fixed rate 2.95% due 2017 and 3.70% due 2020 [Member]
Debt Instrument [Line Items]
Long-term debt, Including current installments on long-term debt	12,000,000	0
Term Loans, fixed rate 2.95% due 2017 and 3.70% due 2020 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest Rate	2.95%
Term Loans, fixed rate 2.95% due 2017 and 3.70% due 2020 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest Rate	3.70%
Interest Rate Swaps [Member]
Debt Instrument [Line Items]
Long-term debt, Including current installments on long-term debt	2,952,000	2,409,000
Other notes [Member]
Debt Instrument [Line Items]
Long-term debt, Including current installments on long-term debt	$ 13,000	$ 25,000