Employee Benefit Plans (Details) (USD $)	12 Months Ended												12 Months Ended				0 Months Ended	3 Months Ended	0 Months Ended		3 Months Ended
	Dec. 31, 2013	Dec. 31, 2013 Non-qualified Plan Benefits	Dec. 31, 2012 Non-qualified Plan Benefits	Dec. 31, 2011 Non-qualified Plan Benefits	Dec. 31, 2013 Other Post-retirement Benefits	Dec. 31, 2012 Other Post-retirement Benefits	Dec. 31, 2011 Other Post-retirement Benefits	Dec. 31, 2013 Pension Benefits	Dec. 31, 2012 Pension Benefits	Dec. 31, 2011 Pension Benefits	Dec. 31, 2013 Cash Balance Defined Benefit Pension Plan	Dec. 31, 2013 Non qualified and Post retirement Benefit Plans	Dec. 31, 2013 Defined Contribution 401k Plan	Dec. 31, 2012 Deferred Profit Sharing	Dec. 31, 2012 Minimum Deferred Profit Sharing	Dec. 31, 2012 Maximum Deferred Profit Sharing	Oct. 02, 2013 Natural Materials and Construction	Dec. 31, 2013 Natural Materials and Construction	Oct. 02, 2013 Natural Materials and Construction Defined Contribution 401k Plan Plan	Oct. 02, 2013 Natural Materials and Construction Deferred Profit Sharing	Dec. 31, 2013 Officer Natural Materials and Construction Defined Contribution 401k Plan	Dec. 31, 2013 Non-Officer Employees Natural Materials and Construction Defined Contribution 401k Plan
Defined Benefit Plan Disclosure [Line Items]
One year pension returns (losses)	16.60%
Three year pension returns (losses)	8.70%
Five year pension returns (losses)	11.60%
Long-term average return since plan inception (in percent)	8.60%
Pension contributions								$ 100,000	$ 2,600,000
Description of interest credit rate basis											ten-year U.S. Treasury rate
Accumulated benefit obligation								173,600,000	186,900,000
Estimated net prior service credit, net of tax, that will be recognized in net periodic pension cost in next fiscal year		400,000						(800,000)
Estimated net loss, net of tax, that will be recognized in net periodic pension cost in next fiscal year		100,000						4,000,000
Amortization period of unrecognized gains and losses					5 years
Plans obligations		6,900,000			(12,900,000)	(10,900,000)		(22,000,000)	(47,400,000)
Discount rate		3.50%			4.90%	4.10%	4.90%	4.90%	4.10%	4.80%
Net periodic benefit cost		100,000	900,000	1,600,000	(200,000)	400,000	900,000	6,200,000	7,300,000	6,400,000
Amount recognized in accumulated other comprehensive income for unrecognized loss, net of tax		(1,800,000)			(1,100,000)	1,400,000		(33,200,000)	(53,000,000)
Unrecognized prior service credit (net of taxes)		2,100,000			0	0		3,900,000	4,400,000
Current liabilities related to non-qualified plan and post-retirement benefits					900,000	800,000		0	0			(1,100,000)
Employer matching contribution, percentage													3.00%		1.00%	5.00%					0.00%	10.00%
Company's matching contribution expense													700,000	900,000				700,000
Number of 401K plans																			2
Maximum annual contribution per employee (in percents)																			10.00%	10.00%
Overall combined limitations of 401k and profit sharing per employee																	$ 25,000
Maximum annual contribution, percent of income before income taxes (in percents)																				5.00%