Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Contingencies [Abstract]
Rent expense	$ 29,700,000	$ 29,100,000	$ 27,000,000
Total future minimum property lease commitments	116,300,000
Future minimum lease payments due in 2011	28,600,000
Future minimum lease payments due in 2012	23,300,000
Future minimum lease payments due in 2013	20,900,000
Future minimum lease payments due in 2014	17,100,000
Future minimum lease payments due in 2015	12,500,000
Future minimum lease payments due thereafter	13,900,000
Product Warranty Disclosure [Abstract]
Balance at beginning of year	7,038,000	7,341,000	9,885,000
Additions charged to costs and expenses	8,846,000	5,671,000	4,416,000
Deductions	7,716,000	5,895,000	7,659,000
Other	(21,000)	(79,000)	699,000
Balance at end of year	8,147,000	7,038,000	7,341,000
Outstanding surety bonds	$ 313,000,000