Acquisitions and Divestitures (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Assets of Ready-Mix Concrete Operations:
Total assets of Ready-Mix Concrete Operations	$ 0	$ 27.9
Liabilities of Ready-Mix Concrete Operations:
Total liabilities of Ready-Mix Concrete Operations	0	3.7
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Provision (benefit) for income taxes	(0.8)	1.1	(0.4)
Net income (loss) from discontinued operations	(0.8)	1.8	(1.1)
Ready-mix concrete operations
Assets of Ready-Mix Concrete Operations:
Inventories	0	4.5
Property, plant, and equipment, net	0	16.9
Goodwill	0	6.3
Other	0	0.2
Total assets of Ready-Mix Concrete Operations	0	27.9
Liabilities of Ready-Mix Concrete Operations:
Debt	0	3.7
Total liabilities of Ready-Mix Concrete Operations	0	3.7
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues	31.6	121.4	136.8
Income (loss) from discontinued operations before income taxes	(1.6)	2.9	(1.5)
Provision (benefit) for income taxes	(0.8)	1.1	(0.4)
Net income (loss) from discontinued operations	$ (0.8)	$ 1.8	$ (1.1)