Financial Commitments (Details 2) (USD $)			12 Months Ended		12 Months Ended				12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Term Loan	Dec. 31, 2012 Term Loan	Dec. 31, 2013 Revolving credit facility	Dec. 31, 2012 Revolving credit facility	Mar. 31, 2012 Revolving credit facility	Aug. 03, 2011 Revolving credit facility	Dec. 31, 2013 Revolving credit facility Minimum	Dec. 31, 2013 Revolving credit facility Maximum	Dec. 31, 2013 Revolving credit facility LIBOR	Dec. 31, 2013 Revolving credit facility LIBOR Minimum	Dec. 31, 2013 Revolving credit facility LIBOR Maximum	Dec. 31, 2013 Revolving credit facility Federal Funds	Dec. 31, 2013 Revolving credit facility Prime rate	Dec. 31, 2013 Revolving credit facility Q3 and Q4 2012	Dec. 31, 2013 Revolving credit facility Q1 and Q2 2013	Dec. 31, 2013 Revolving credit facility Q3 2013 and thereafter	Dec. 31, 2013 Revolving credit facility Q3 2012 thru Q1 2013	Dec. 31, 2013 Revolving credit facility Q2 2013 thru Q4 2013	Dec. 31, 2013 Revolving credit facility Q1 2014 thru Q3 2014	Dec. 31, 2013 Revolving credit facility Q4 2014 and thereafter	Aug. 03, 2012 Letters of credit outstanding	Aug. 02, 2012 Letters of credit outstanding	Aug. 03, 2011 Letters of credit outstanding
Amended Credit Agreement
Maximum borrowing capacity								$ 300,000,000															$ 150,000,000	$ 50,000,000	$ 50,000,000
Percentage of consolidated net worth that is factored into consolidated net worth covenant							85.00%
Maximum goodwill and intangible assets impairment charge added back to covenants					450,000,000
Percentage of net income for each fiscal quarter (with no deduction for net losses) factored into consolidated net worth covenant					50.00%
Percentage of aggregate amount of all equity issuances that increase stockholder's equity factored into consolidated net worth covenant					100.00%
Minimum fixed charge ratio																1.00	1.10	1.25
Maximum consolidated leverage ratio																			4.25	3.75	3.25	2.75
Reference rate											British Bankers Association LIBOR rate			Federal Funds Rate	Bank of America prime rate
Basis points added to reference rate (as a percent)												2.00%	4.00%	0.50%	3.00%
Facility fees (as a percent)									0.375%	0.70%
Period of term loan			5 years
Loan outstanding	733,884,000	737,090,000	115,000,000	152,500,000
Outstanding borrowings					135,000,000	120,000,000
Letters of credit outstanding					200,000	200,000
Available borrowing capacity					$ 164,900,000