Pension Plans and Other Postretirement Benefits (Details-3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Real Estate [Member]
Fixed Income Securities:
Fair value of plan assets	$ 15,565	$ 11,604
Changes in fair value of Level 3 assets [Roll Forward]
Fair value of plan assets at beginning of year	11,604	10,210
Actual return on plan assets still held	2,149	1,145
Actual return on plan assets sold during period	0	(4)
Purchases, sales, and settlements	1,812	253
Fair value of plan assets at end of year	15,565	11,604
Insurance Continuance Fund [Member]
Fixed Income Securities:
Fair value of plan assets	906	1,003
Changes in fair value of Level 3 assets [Roll Forward]
Fair value of plan assets at beginning of year	1,003	1,008
Actual return on plan assets still held	46	48
Actual return on plan assets sold during period	0	0
Purchases, sales, and settlements	(143)	(53)
Fair value of plan assets at end of year	906	1,003
Plan Assets [Member]
Assets:
Cash and cash equivalents	2,436	2,036
Equity Securities:
U.S. Large Cap	57,629	54,688
U.S. Mid Cap	13,987	14,115
U.S. Small Cap	18,468	18,189
International Blend	32,847	32,847
Fixed Income Securities:
Short-Term Fund	2,961	2,227
High Yield Bond	9,829	8,535
Long Duration Bond	42,139	35,059
Real Estate	15,565	11,604
Insurance Continuance Fund	906	1,003
Fair value of plan assets	196,767	180,303
Changes in fair value of Level 3 assets [Roll Forward]
Fair value of plan assets at end of year	196,767	180,303
Plan Assets [Member] \| Level 1 [Member]
Assets:
Cash and cash equivalents	2,436	2,036
Equity Securities:
U.S. Large Cap	0	0
U.S. Mid Cap	0	0
U.S. Small Cap	0	0
International Blend	0	0
Fixed Income Securities:
Short-Term Fund	0	0
High Yield Bond	0	0
Long Duration Bond	0	0
Real Estate	0	0
Insurance Continuance Fund	0	0
Fair value of plan assets	2,436	2,036
Changes in fair value of Level 3 assets [Roll Forward]
Fair value of plan assets at end of year	2,436	2,036
Plan Assets [Member] \| Level 2 [Member]
Assets:
Cash and cash equivalents	0	0
Equity Securities:
U.S. Large Cap	57,629	54,688
U.S. Mid Cap	13,987	14,115
U.S. Small Cap	18,468	18,189
International Blend	32,847	32,847
Fixed Income Securities:
Short-Term Fund	2,961	2,227
High Yield Bond	9,829	8,535
Long Duration Bond	42,139	35,059
Real Estate	0	0
Insurance Continuance Fund	0	0
Fair value of plan assets	177,860	165,660
Changes in fair value of Level 3 assets [Roll Forward]
Fair value of plan assets at end of year	177,860	165,660
Plan Assets [Member] \| Level 3 [Member]
Assets:
Cash and cash equivalents	0	0
Equity Securities:
U.S. Large Cap	0	0
U.S. Mid Cap	0	0
U.S. Small Cap	0	0
International Blend	0	0
Fixed Income Securities:
Short-Term Fund	0	0
High Yield Bond	0	0
Long Duration Bond	0	0
Real Estate	15,565	11,604
Insurance Continuance Fund	906	1,003
Fair value of plan assets	16,471	12,607
Changes in fair value of Level 3 assets [Roll Forward]
Fair value of plan assets at end of year	$ 16,471	$ 12,607

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