Retirement Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
401 (k) Plan [Member]
Defined Contribution Plans [Line Items]
Contribution to plan			$ 1,000,000
Pension expense			3,600,000
Discretionary contribution	2,400,000	1,900,000	1,500,000
SERP [Member]
Defined Contribution Plans [Line Items]
Contribution to plan			67,000
Curtailment costs			666,000
Distribution from SERP	402,000
Liability due to participants	$ 2,100,000	$ 2,200,000