Accounting Policies and Basis of Presentation (Details) (USD $)	3 Months Ended		1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 30, 2013	Mar. 31, 2012	Jan. 28, 2012 PS International	Mar. 31, 2012 PS International	Dec. 31, 2012 PS International	Jan. 02, 2012 PS International
Equity method investments
Percentage ownership acquired						50.00%
Ownership after increase (as a percent)			70.00%		85.00%
Total cash paid, net of cash acquired		$ 2,825,000	$ 2,825,000	$ 2,825,000
Increase in working capital				14,419,000
Increase in fixed assets				163,000
Increase in goodwill				2,590,000
Increase in intangible assets				621,000
Increase in other long-term assets				96,000
Increase in non-controlling interest				5,649,000
Decrease in investments in and advances to affiliates				9,415,000
Non-cash, pay-in-kind interest income and accretion of discount recognized on a note receivable from an affiliate	$ 3,111,000	$ 2,818,000