Acquisitions and Divestitures (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Acquisitions:
Total cost		$ 70.5
Net cash paid	42.5	49.9
Goodwill recorded		33.3
Divestitures:
Proceeds		30.8
Gain recognized		3.8
Goodwill charged off		16.5
Construction Products Group [Member]
Acquisitions:
Total cost	56.4	63.1
Net cash paid	42.5	44.9
Goodwill recorded	29.3	26.7
Divestitures:
Proceeds	8.3	30.8
Gain recognized	0.7	3.8
Goodwill charged off	1.0	16.5
Construction Products Group [Member] | Quixote [Member]
Acquisitions:
Total cost		58.1
Net cash paid		39.9
Goodwill recorded		22.7
Construction Products Group [Member] | Other acquisitions [Member]
Acquisitions:
Total cost		5.0
Net cash paid		5.0
Goodwill recorded		4.0
Divestitures:
Proceeds		30.8
Gain recognized		3.8
Goodwill charged off		16.5
Energy Equipment Group [Member]
Acquisitions:
Total cost		7.4
Net cash paid		5.0
Goodwill recorded		$ 6.6