Employee Benefit Plans (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Pension Plans Defined Benefit Member
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Service Cost	$ 1,910,000	$ 1,312,000	$ 5,638,000	$ 4,324,000
Defined Benefit Plan Interest Cost	1,065,000	971,000	3,135,000	2,913,000
Expected return on plan assets	(766,000)	(734,000)	(2,299,000)	(2,203,000)
Defined Benefit Plan Amortization Of Prior Service Cost Credit	102,000	195,000	288,000	296,000
Amortization of prior actuarial loss	851,000	658,000	2,514,000	1,160,000
Total	3,162,000	2,402,000	9,276,000	6,490,000
Other Postretirement Benefit Plans Defined Benefit Member
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Service Cost	673,000	413,000	1,231,000	837,000
Defined Benefit Plan Interest Cost	418,000	335,000	935,000	776,000
Expected return on plan assets	0	0	0	0
Defined Benefit Plan Amortization Of Prior Service Cost Credit	0	0	0	0
Amortization of prior actuarial loss	380,000	147,000	557,000	265,000
Total	$ 1,471,000	$ 895,000	$ 2,723,000	$ 1,878,000