Postretirement Benefit Plans (Details 14) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined contribution plan expenses for the company's retirement savings plans and profit sharing plan
Total	$ 10,046,000	$ 8,802,000	$ 9,370,000
Retirement Savings Plans [Member]
Defined contribution plan expenses for the company's retirement savings plans and profit sharing plan
Total	4,284,000	4,033,000	4,309,000
Profit Sharing Plan [Member]
Defined contribution plan expenses for the company's retirement savings plans and profit sharing plan
Total	$ 5,762,000	$ 4,769,000	$ 5,061,000