Restructuring - Additional Information (Detail) (USD $)	12 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Apr. 11, 2011 2011 Restructuring Program Person	Dec. 31, 2012 Residential Real Estate	Dec. 31, 2011 Residential Real Estate	Dec. 31, 2012 Commercial Real Estate	Dec. 31, 2011 Commercial Real Estate	Dec. 31, 2012 Rural land	Dec. 31, 2011 Rural land	Dec. 31, 2012 Forestry	Dec. 31, 2011 Forestry	Dec. 31, 2012 Corporate and Other [Member]	Dec. 31, 2011 Corporate and Other [Member]
Restructuring Cost and Reserve [Line Items]
Number of senior management members entered into separation agreements			4
Restructuring costs incurred		$ 10,900,000
2011 and prior restructuring and relocation programs
Restructuring Reserve	790,000	960,000		341,000	239,000	186,000	9,000	149,000	36,000	0	19,000	114,000	657,000
Costs Accrued (Adjustments)	0	11,551,000		(24,000)	699,000	(186,000)	1,657,000	(145,000)	196,000	0	77,000	355,000	8,922,000
Payments	745,000	11,721,000		317,000	597,000	0	1,480,000	4,000	83,000	0	96,000	424,000	9,465,000
Restructuring Reserve	45,000	790,000		0	341,000	0	186,000	0	149,000	0	0	45,000	114,000
Cumulative Charges	$ 48,715,000			$ 20,153,000		$ 2,818,000		$ 2,617,000		$ 571,000		$ 22,556,000