Income Taxes (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
U.S. federal statutory income tax rate and effective tax rate
U.S. federal statutory income tax rate (as a percent)	35.00%	35.00%	35.00%
State and local income taxes, net of U.S. federal income tax effect (as a percent)	1.80%	2.20%	6.00%
Foreign tax impact, net (as a percent)	(3.60%)	(0.90%)	9.80%
Non-deductible costs (as a percent)	(24.30%)	(23.70%)	1.10%
Other, net (as a percent)	(0.50%)	0.40%	(0.50%)
Effective income tax rate (as a percent)	8.40%	13.00%	51.40%
Increase in current taxes payable	$ 4,100,000	$ 3,300,000	$ 2,200,000
Unrecognized tax benefits
Uncertain income tax positions not recognized, if percentage is less than, likelihood of being sustained	50.00%
Decrease in income tax liability due to resolution of uncertain tax positions in the U.S.	1,900,000
Decrease in deferred tax assets due to uncertain tax positions	700,000
Tax benefits	900,000
Reconciliation of the beginning and ending amounts of unrecognized tax benefits
Uncertain Tax Benefits, balance at the beginning of the period	14,542,000	12,380,000	10,999,000
Additions based on tax positions related to the current year	568,000	2,402,000	2,088,000
Additions based on tax positions of prior years	857,000	647,000	897,000
Reductions for tax positions of prior years	(2,024,000)	(42,000)	(35,000)
Reductions due to settlements with taxing authorities	(217,000)	(516,000)	(758,000)
Reductions due to expiration of statute of limitations		(329,000)	(811,000)
Uncertain Tax Benefits, balance at the end of the period	13,726,000	14,542,000	12,380,000
Unrecognized tax benefits (net of federal benefits) if recognized will affect the entity's effective tax rate	12,400,000	12,000,000	10,800,000
Accrued interest expense related to unrecognized tax benefits, gross of tax	3,300,000
Tax effect of interest accrued on unrecognized tax benefits	1,400,000
Company recognized interest expense	800,000	700,000	500,000
Penalties recognized, as a component of income tax expense			$ 100,000