Derivative Financial Instruments (Details Textual)	3 Months Ended		6 Months Ended				3 Months Ended	6 Months Ended
	Jun. 30, 2013 USD ($)	Jul. 01, 2012 USD ($)	Jun. 30, 2013 USD ($) agreement	Jul. 01, 2012 USD ($)	Jun. 30, 2013 AUD	Dec. 31, 2012 USD ($)	Jun. 30, 2013 Fair Value Hedging Interest Rate Swap USD ($)	Jun. 30, 2013 Fair Value Hedging Interest Rate Swap USD ($)	Jun. 30, 2013 Minimum	Jun. 30, 2013 Maximum
Derivative Instruments, Gain (Loss) [Line Items]
Gains (loss) recognized and recorded in earnings related to fair value hedge							$ 900,000	$ 1,600,000
Interest Rate Swaps [Abstract]
Number of Interest Rate Swap Agreements			4
Interest rate	7.75%		7.75%
Notional amount coincide with the terms of the non-recourse debt	100,000,000		100,000,000
Variable interest rate payment to the same counterparties									4.16%	4.29%
Fair value of the swap assets included as Other Non-Current Assets	4,600,000		4,600,000			6,200,000
Ineffective portion of Fair value interest rate swap	0	0
Fixed interest rate on cash flow interest rate derivative	9.70%		9.70%
Interest Rate Swap Agreements					50,900,000
Net unrealized loss recognized in the periods and recorded in accumulated other comprehensive income, net of tax	0		100,000
Interest Rate Cash Flow Hedge Liability at Fair Value	500,000		500,000			700,000
Ineffective portion of Cash Flow Hedge interest rate swap	$ 0	$ 0	$ 0	$ 0