Debt Credit Facility Additional Information (Details) (USD $)	12 Months Ended								12 Months Ended
	Dec. 31, 2011 2007 Senior Secured Credit Facility [Member]	Dec. 31, 2012 2011 Senior Secured Credit Facility [Member]	Apr. 02, 2012 2011 Senior Secured Credit Facility [Member]	Dec. 31, 2011 2011 Senior Secured Credit Facility [Member]	Aug. 05, 2011 2011 Senior Secured Credit Facility [Member]	Dec. 31, 2012 2011 Senior Secured Credit Facility [Member] Line of Credit [Member]	Aug. 05, 2011 2011 Senior Secured Credit Facility [Member] Line of Credit [Member]	Dec. 31, 2012 2011 Senior Secured Credit Facility [Member]	Dec. 31, 2012 U.S. Domestic Subsidiaries [Member]	Dec. 31, 2012 First-Tier Foreign Subsidiaries [Member] Non-voting Stock [Member]	Dec. 31, 2012 Scheduled Quarterly Repayments through June 2013 [Domain]	Dec. 31, 2012 Scheduled Quarterly Repayments September 2013 through June 2014 [Domain]	Dec. 31, 2012 Scheduled Quarterly Repayments September 2014 through June 2016 [Domain]	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Maximum [Member]	Dec. 31, 2012 Maximum [Member] First-Tier Foreign Subsidiaries [Member] Voting Stock [Member]	Dec. 31, 2012 Alternate base rate [Member]	Dec. 31, 2012 Alternate base rate [Member] 2011 Senior Secured Credit Facility [Member]	Dec. 31, 2012 LIBOR interest rate [Member] 2011 Senior Secured Credit Facility [Member]
Debt Instrument [Line Items]
Proceeds from borrowings		$ 80,000,000
Debt Instrument, Face Amount								300,000,000
Line of credit facility, maximum borrowing capacity						660,000,000	500,000,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage														0.20%	0.40%
Pledge of Capital Stock									100.00%	100.00%						66.00%
Repayments of Secured Debt											3,800,000	5,600,000	7,500,000
Debt Instrument, Interest Rate at Period End																			1.47%
Debt Instrument, Basis Spread on Variable Rate																	0.50%	1.00%	1.25%
Multicurrency revolving line of credit		140,000,000		160,000,000		140,000,000
Letters of Credit Outstanding, Amount						54,300,000
Line of credit facility, remaining borrowing capacity						465,700,000
Write-off of unamortized prepaid debt fees	2,400,000
Unamortized prepaid debt fees			$ 897,000		$ 6,600,000