Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2011

Compensation and Retirement Disclosure [Abstract]

Schedule of Allocation of Plan Assets [Table Text Block]

The Corporation's pension plan weighted-average allocations at measurement dates by asset category are as follows:

	Percentage of Plan Assets on Measurement Date
	December 31,
Asset Category	2011		2010
Cash and domestic money market funds	4.33	%	4.39	%
U.S. Treasury obligations	2.37	%	2.97	%
U.S. Government agencies	2.96	%	3.33	%
Corporate bonds	5.22	%	5.38	%
Common stocks	15.30	%	24.56	%
Equity mutual funds	36.80	%	23.26	%
Fixed income mutual funds	18.89	%	19.84	%
Foreign mutual funds	14.13	%	16.27	%
	100.00	%	100.00	%

The Corporation's asset allocation strategy favors equities, with a target allocation of approximately 90% equity securities. The asset allocation policy is as below:
Asset Class	Target		Range
Large Cap U.S. Equity	45.00	%	35% to 55%
Small/Mid Cap U.S. Equity	20.00	%	10% to 30%
International Equity	25.00	%	15% to 35%
Alternative Investments	10.00	%	0% to 15%
	100.00	%

Schedule of Assumptions Used [Table Text Block]

The actuarial assumptions used in the defined benefit qualified and nonqualified pension plans and the postretirement medical and life insurance benefit plan were as follows:

	Pension Benefits						Postretirement Benefits
Weighted-average assumptions as of 12/31 measurement date	2011		2010		2009		2011		2010		2009
Discount Rate	5.04	%	5.60	%	5.98	%	4.23	%	4.43	%	4.94	%
Long-term rate of return on assets	7.25	%	8.25	%	8.50	%	—		—		—
Rate of compensation increase	3.75% to 5.22%		3.75% to 5.22%		3.75% to 5.22%		—		—		—
Medical trend rates - non-medicare risk Pre-65	—		—		—		8.5% to 5.0%		9.0% to 5.0%		7.0% to 5.0%
Medical trend rates - non-medicare risk Post-65	—		—		—		12.5% to 5.0%		13.0% to 5.0%		9.0% to 5.0%
Prescription Drugs	—		—		—		8.5% to 5.0%		9.0% to 5.0%		9.0% to 5.0%
Medical trend rates - medicare risk HMO Post-65							12.5% to 5.0%		13.0% to 5.0%		9.0% to 5.0%

Schedule of Net Benefit Costs [Table Text Block]

The following table sets forth the plans' funded status and amounts recognized in the Corporation's consolidated financial statements.
	Pension Benefits						Postretirement Benefits
	2011			2010			2011			2010
Change in projected benefit obligation:
(PBO), beginning of year	$	211,183		$	193,359		$	19,942		$	19,675
Service cost	6,123			5,919			54			61
Interest cost	11,439			11,200			886			959
Plan amendments	—			—			(4,794		)	—
Participant contributions	—			—			846			509
Actuarial gain	23,727			8,512			1,578			954
Benefits paid	(8,832		)	(7,807		)	(2,262		)	(2,216		)
PBO, end of year	$	243,640		$	211,183		$	16,250		$	19,942
Change in plan assets, at fair value:
Fair value of plan assets, beginning of year	$	152,390		$	122,799		$	—		$	—
Actual return on plan assets	(1,352		)	16,130			—			—
Participant contributions	—			—			846			509
Employer contributions	11,399			21,268			1,416			1,707
Benefits paid	(8,832		)	(7,807		)	(2,262		)	(2,216		)
Fair value of plan assets, end of year	$	153,605		$	152,390		$	—		$	—
Funded status	(90,046		)	(58,793		)	(16,250		)	(19,942		)
Prior service costs	1,909			2,303			(4,794		)	—
Cumulative net loss	117,664			86,381			4,624			3,160
Prepaid (accrued) pension/postretirement cost	29,527			29,891			(16,420		)	(16,782		)
Amounts recognized in the statement of financial condition consist of:
Accrued benefit liability	$	(90,046	)	$	(58,793	)	$	(16,250	)	$	(19,942	)
Intangible asset	—			—			—			—
Accumulated other comprehensive income	119,573			88,684			(170		)	3,160
Net amount recognized	$	29,527		$	29,891		$	(16,420	)	$	(16,782	)

Schedule of Net Funded Status [Table Text Block]

The following table sets forth the plans' funded status and amounts recognized in the Corporation's consolidated financial statements.
	Pension Benefits						Postretirement Benefits
	2011			2010			2011			2010
Change in projected benefit obligation:
(PBO), beginning of year	$	211,183		$	193,359		$	19,942		$	19,675
Service cost	6,123			5,919			54			61
Interest cost	11,439			11,200			886			959
Plan amendments	—			—			(4,794		)	—
Participant contributions	—			—			846			509
Actuarial gain	23,727			8,512			1,578			954
Benefits paid	(8,832		)	(7,807		)	(2,262		)	(2,216		)
PBO, end of year	$	243,640		$	211,183		$	16,250		$	19,942
Change in plan assets, at fair value:
Fair value of plan assets, beginning of year	$	152,390		$	122,799		$	—		$	—
Actual return on plan assets	(1,352		)	16,130			—			—
Participant contributions	—			—			846			509
Employer contributions	11,399			21,268			1,416			1,707
Benefits paid	(8,832		)	(7,807		)	(2,262		)	(2,216		)
Fair value of plan assets, end of year	$	153,605		$	152,390		$	—		$	—
Funded status	(90,046		)	(58,793		)	(16,250		)	(19,942		)
Prior service costs	1,909			2,303			(4,794		)	—
Cumulative net loss	117,664			86,381			4,624			3,160
Prepaid (accrued) pension/postretirement cost	29,527			29,891			(16,420		)	(16,782		)
Amounts recognized in the statement of financial condition consist of:
Accrued benefit liability	$	(90,046	)	$	(58,793	)	$	(16,250	)	$	(19,942	)
Intangible asset	—			—			—			—
Accumulated other comprehensive income	119,573			88,684			(170		)	3,160
Net amount recognized	$	29,527		$	29,891		$	(16,420	)	$	(16,782	)

Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block]

Information for those pension plans that had an ABO in excess of plan assets is as follows:

	Pension Benefits				Postretirement Benefits
	2011		2010		2011	2010
Aggregate projected benefit obligation	$	243,640	$	211,183	n/a	n/a
Aggregate accumulated benefit obligation	220,932		190,828		n/a	n/a
Aggregate fair value of plan assets	153,605		152,390		n/a	n/a

Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]

Amounts recognized in accumulated other comprehensive loss consist of:

	Pension Benefits				Postretirement Benefits
	2011		2010		2011			2010
Prior service cost	$	1,909	$	2,303	$	(4,794	)	$	—
Cumulative net loss	117,664		86,381		4,624			3,160
Total amount recognized	$	119,573	$	88,684	$	(170	)	$	3,160

Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year [Table Text Block]

The amounts in accumulated other comprehensive loss that are expected to be recognized as components of net periodic benefit cost (credit) during the next fiscal year are as follows:

	Pension		Postretirement			Total
Prior service cost	$	388	$	(468	)	$	(80	)
Cumulative net loss	10,371		287			10,658

Schedule of Defined Benefit Plans Disclosures [Table Text Block]

The following table sets forth by level, within the fair value hierarchy, the pension plans’ assets at fair value as of December 31, 2011:

	Level 1		Level 2		Level 3		Total
Domestic money market funds	$	6,654	$	—	$	—	$	6,654
United States government securities	—		3,646		—		3,646
United States government agency issues	—		4,550		—		4,550
Corporate bonds	—		8,024		—		8,024
Common stocks	23,494		—		—		23,494
Equity mutual funds	56,529		—		—		56,529
Fixed income mutual funds	29,012		—		—		29,012
Foreign mutual funds	21,695		—		—		21,695
Total assets at fair value	$	137,384	$	16,220	$	—	$	153,604