Financial Commitments (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Swap [Member]
Debt Instrument [Line Items]
Maximum adjustment to Applicable Rate (in hundredths)	0.975%
Term Loan [Member]
Debt Instrument [Line Items]
Term loan amount	$ 200
Term of loan	5 years
Term loan amount outstanding	161.3
Revolving Credit Facility [Member]
Amended Credit Agreement [Abstract]
Original sublimit for letters of credit	50
Amended sublimit for letters of credit	150
Percentage of consolidated net worth that is factored into consolidated net worth covenant (in hundredths)		85.00%
Maximum goodwill and intangible assets impairment charge added back to covenants	450.0
Percentage of net income for each fiscal quarter (with no deduction for net losses) factored into consolidated net worth covenant (in hundredths)	50.00%
Percentage of aggregate amount of all equity issuances that increase stockholder's equity factored into consolidated net worth covenant (in hundredths)	100.00%
Minimum fixed charge ratio, quarter ending September 30, 2012 (in hundredths)	1.00
Minimum fixed charge ratio, quarter ending December 30, 2012 (in hundredths)	1.00
Minimum fixed charge ratio, quarter ending March 31, 2013 (in hundredths)	1.10
Minimum fixed charge ratio, quarter ending June 30, 2013 (in hundredths)	1.10
Minimum fixed charge ratio, quarter ending September 30, 2013 and thereafter (in hundredths)	1.25
Maximum consolidated leverage ratio, quarter ending September 30, 2012 (in hundredths)	4.25
Maximum consolidated leverage ratio, quarter ending December 31, 2012 (in hundredths)	4.25
Maximum consolidated leverage ratio, quarter ending March 31, 2013 (in hundredths)	4.25
Maximum consolidated leverage ratio, quarter ending June 30, 2013 (in hundredths)	3.75
Maximum consolidated leverage ratio, quarter ending September 30, 2013 (in hundredths)	3.75
Maximum consolidated leverage ratio, quarter ending December 31, 2013 (in hundredths)	3.75
Maximum consolidated leverage ratio, quarter ending March 31, 2014 (in hundredths)	3.25
Maximum consolidated leverage ratio, quarter ending June 30, 2014 (in hundredths)	3.25
Maximum consolidated leverage ratio, quarter ending September 30, 2014 (in hundredths)	3.25
Maximum consolidated leverage ratio, quarter ending December 31, 2014 and thereafter (in hundredths)	2.75
Minimum adjustment to British Bankers Association LIBOR rate (in hundredths)	2.00%
Maximum adjustment to British Bankers Association LIBOR rate (in hundredths)	4.00%
Maximum adjustment to Federal Funds rate (in hundredths)	0.50%
Maximum adjustment to Bank of America, N.A. prime rate (in hundredths)	3.00%
Minimum commitment fee percentage (in hundredths)	0.375%
Maximum commitment fee percentage (in hundredths)	0.70%
Maximum borrowing capacity	300
Additional increase in base facility	50
Outstanding borrowings	70.0		0
Letters of credit outstanding	0.2		3.0
Available borrowing capacity	$ 229.8