Accounts Payable and Accrued Expenses (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts Payable and Accrued Expenses
Accounts payable	$ 196,522	$ 211,890
Book overdraft	14,851	5,171
Accrued accounts payable	121,556	108,385
Accrued liabilities	45,942	39,585
Payroll and employee benefits	41,662	40,356
Accrued interest	39,804	41,253
Taxes, other than income	41,133	57,795
Income taxes	459	7,911
Accounts payable and accrued expenses	$ 501,929	$ 512,346