Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
2004 [Member]
Insurance coverage
Policy year	2004
Policy start date	Dec. 01, 2003
Policy end date	Dec. 01, 2004
Insurance coverage	$ 2.0
Deductible amount	0.1
Defense costs covered	N
Remaining insurance covered	2.0
Active Cases and Cases on Appeal	Glowczenski
2005 [Member]
Insurance coverage
Policy year	2005
Policy start date	Dec. 01, 2004
Policy end date	Dec. 01, 2005
Insurance coverage	10.0
Deductible amount	0.3
Defense costs covered	Y
Remaining insurance covered	7.0
Active Cases and Cases on Appeal	Washington
2006 [Member]
Insurance coverage
Policy year	2006
Policy start date	Dec. 01, 2005
Policy end date	Dec. 01, 2006
Insurance coverage	10.0
Deductible amount	0.3
Defense costs covered	Y
Remaining insurance covered	4.0
Active Cases and Cases on Appeal	Stough, Hollman
2007 [Member]
Insurance coverage
Policy year	2007
Policy start date	Dec. 01, 2006
Policy end date	Dec. 01, 2007
Insurance coverage	10.0
Deductible amount	0.3
Defense costs covered	Y
Remaining insurance covered	8.0
Active Cases and Cases on Appeal	n/a
2008 [Member]
Insurance coverage
Policy year	2008
Policy start date	Dec. 01, 2007
Policy end date	Dec. 15, 2008
Insurance coverage	10.0
Deductible amount	0.5
Defense costs covered	Y
Remaining insurance covered	5.5
Active Cases and Cases on Appeal	Salinas, Grable, Koon, Peppler, Rich, Turner
2009 [Member]
Insurance coverage
Policy year	2009
Policy start date	Dec. 15, 2008
Policy end date	Dec. 15, 2009
Insurance coverage	10.0
Deductible amount	1.0
Defense costs covered	N
Remaining insurance covered	10.0
Active Cases and Cases on Appeal	Athetis, Kandt, Humpherys, Derbyshire
2010 [Member]
Insurance coverage
Policy year	2010
Policy start date	Dec. 15, 2009
Policy end date	Dec. 15, 2010
Insurance coverage	10.0
Deductible amount	1.0
Defense costs covered	N
Remaining insurance covered	10.0
Active Cases and Cases on Appeal	Thompson, Jacobs, Kelley, Shymko, Doan, Piskura, Juran, Fahy
2011 [Member]
Insurance coverage
Policy year	2011
Policy start date	Dec. 15, 2010
Policy end date	Dec. 15, 2011
Insurance coverage	10.0
Deductible amount	1.0
Defense costs covered	N
Remaining insurance covered	10.0
Active Cases and Cases on Appeal	Butler, Wilson, Sylvester, Nelson, Bachtel. Coto, Russell, Payne
Jan - Jun 2012 [Member]
Insurance coverage
Policy start date	Dec. 15, 2012
Policy end date	Jun. 25, 2012
Insurance coverage	7.0
Deductible amount	1.0
Defense costs covered	N
Remaining insurance covered	7.0
Active Cases and Cases on Appeal	Ramsey, Duensing, Mitchell, Firman, Ricks
Jan - Jun 2012 [Member] | Maximum [Member]
Insurance coverage
Policy month year	2012-06
Jan - Jun 2012 [Member] | Minimum [Member]
Insurance coverage
Policy month year	2012-01
Jul - Dec 2012 [Member]
Insurance coverage
Policy start date	Jun. 25, 2012
Policy end date	Dec. 15, 2012
Insurance coverage	12.0
Deductible amount	1.0
Defense costs covered	N
Remaining insurance covered	$ 12.0
Active Cases and Cases on Appeal	Neil, Norman, Wingard
Jul - Dec 2012 [Member] | Maximum [Member]
Insurance coverage
Policy month year	2012-12
Jul - Dec 2012 [Member] | Minimum [Member]
Insurance coverage
Policy month year	2012-07