Employee Benefit Plans (Periodic Benefit Expense Net) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011 years	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Employee Benefit Plans
Service cost	$ 999,000	$ 486,000	$ 3,013,000	$ 811,000
Interest cost	307,000	436,000	651,000	811,000
Expected return on assets	(787,000)	(1,518,000)	(1,628,000)	(2,943,000)
Prior service costs	173,000	200,000	351,000	375,000
Settlement loss		1,592,000		1,592,000
Curtailment charges	1,713,000	1,347,000	1,713,000	1,347,000
Net periodic benefit expense	2,405,000	2,543,000	4,100,000	1,993,000
Reduction in retiree medical liability	$ 7,000,000		$ 7,000,000
Change in accumulated other comprehensive income will be amortized into income over the future life expectancy of the participants	9