Debt (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Short-term debt and current portion of long-term debt:
Short-term debt	9,820	5,091
Current portion of long-term debt, including capital leases	358,155	269,275
Total short-term debt and current portion of long-term debt	367,975	274,366
Short-term debt [Member]
Short-term debt and current portion of long-term debt:
Short-term debt, Weighted Average Interest Rate	2.27%	1.45%
Maturity date range, start	Jan. 01, 2013