Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2012

Compensation and Retirement Disclosure [Abstract]

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	2012		2011		2010		2012		2011		2010
Discount Rate	4.21	%	5.04	%	5.60	%	3.18	%	4.23	%	4.43	%
Long-term rate of return on assets	7.00	%	7.25	%	8.25	%	—		—		—
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	—		—		—		8.0% to 5.0%		8.5% to 5.0%		9.0% to 5.0%
Medical trend rates - non-medicare risk Post-65	—		—		—		12.0% to 5.0%		12.5% to 5.0%		13.0% to 5.0%
Prescription Drugs	—		—		—		8.0% to 5.0%		8.5% to 5.0%		9.0% to 5.0%
Medical trend rates - medicare risk HMO Post-65	—		—		—		12.0% to 5.0%		12.5% to 5.0%		13.0% to 5.0%

Schedule of Net Benefit Costs [Table Text Block]

	Pension Benefits									Postretirement Benefits
	2012			2011			2010			2012			2011		2010
Service cost	$	7,194		$	6,123		$	5,919		$	77		$	54	$	61
Interest cost	11,862			11,439			11,200			697			886		959
Expected return on assets	(12,136		)	(13,313		)	(12,059		)	—			—		—
Prior service costs	388			394			394			(468		)	—		—
Cumulative net loss	10,371			7,120			5,708			288			114		15
Curtailment gain	(142		)	—			—			—			—		—
Net periodic pension/postretirement cost (benefit)	$	17,537		$	11,763		$	11,162		$	594		$	1,054	$	1,035

Schedule of Net Funded Status [Table Text Block]

	Pension Benefits						Postretirement Benefits
	2012			2011			2012			2011
Change in projected benefit obligation:
(PBO), beginning of year	$	243,640		$	211,183		$	16,250		$	19,942
Service cost	7,194			6,123			77			54
Interest cost	11,862			11,439			697			886
Plan amendments	—			—			—			(4,794		)
Participant contributions	—			—			1,199			846
Actuarial gain	8,529			23,727			(58		)	1,578
Benefits paid	(11,797		)	(8,832		)	(3,394		)	(2,262		)
PBO, end of year	$	259,428		$	243,640		$	14,771		$	16,250
Change in plan assets, at fair value:
Fair value of plan assets, beginning of year	$	153,605		$	152,390		$	—		$	—
Actual return on plan assets	19,372			(1,352		)	—			—
Participant contributions	—			—			1,199			846
Employer contributions	13,205			11,399			2,195			1,416
Benefits paid	(11,797		)	(8,832		)	(3,394		)	(2,262		)
Fair value of plan assets, end of year	$	174,385		$	153,605		$	—		$	—
Funded status	(85,043		)	(90,046		)	(14,771		)	(16,250		)
Prior service costs	1,663			1,909			(4,326		)	(4,794		)
Cumulative net loss	108,572			117,664			4,279			4,624
Prepaid (accrued) pension/postretirement cost	25,192			29,527			(14,818		)	(16,420		)
Amounts recognized in the statement of financial condition consist of:
Accrued benefit liability	$	(85,043	)	$	(90,046	)	$	(14,771	)	$	(16,250	)
Accumulated other comprehensive income	110,235			119,573			(47		)	(170		)
Net amount recognized	$	25,192		$	29,527		$	(14,818	)	$	(16,420	)

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
	2012		2011		2012	2011
Aggregate projected benefit obligation	$	259,428	$	243,640	n/a	n/a
Aggregate accumulated benefit obligation	257,206		220,932		n/a	n/a
Aggregate fair value of plan assets	174,385		153,605		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
	2012		2011		2012			2011
Prior service cost	$	1,663	$	1,909	$	(4,326	)	$	(4,794	)
Cumulative net loss	108,572		117,664		4,279			4,624
Total amount recognized	$	110,235	$	119,573	$	(47	)	$	(170	)

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	$	469	$	(468	)	$	1
Cumulative net loss	4,696		268			4,964

Investment Allocation Strategy [Table Text Block]

Dynamic Investment Policy Schedule
Return-Seeking (and Diversification) Allocation Strategy
Funded Ratio	Minimum	Target	Maximum
≤80%	58%	65%	72%
81%-83%	55%	62%	69%
84%-86%	52%	58%	64%
87%-89%	47%	53%	59%
90%-92%	43%	49%	55%
93%-95%	39%	44%	49%
96%-98%	35%	40%	45%
99%-101%	31%	35%	39%
102%-104%	27%	31%	35%
105%-107%	22%	26%	30%
107%-110%	18%	22%	26%
>110%	16%	20%	24%

Schedule of Allocation of Plan Assets [Table Text Block]

	Percentage of Plan Assets on Measurement Date
	December 31,
Asset Category	2012		2011
Cash and domestic money market funds	2.97	%	4.33	%
U.S. Treasury obligations	2.34	%	2.37	%
U.S. Government agencies	2.03	%	2.96	%
Corporate bonds	4.55	%	5.22	%
Common stocks	15.43	%	15.30	%
Equity mutual funds	31.35	%	36.80	%
Fixed income mutual funds	24.10	%	18.89	%
Foreign mutual funds	17.23	%	14.13	%
	100.00	%	100.00	%

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, 2012:

	Level 1		Level 2		Level 3		Total
Domestic money market funds	$	5,188	$	—	$	—	$	5,188
United States government securities	—		4,074		—		4,074
United States government agency issues	—		3,542		—		3,542
Corporate bonds	—		7,931		—		7,931
Common stocks	26,916		—		—		26,916
Equity mutual funds	54,663		—		—		54,663
Fixed income mutual funds	42,028		—		—		42,028
Foreign mutual funds	30,043		—		—		30,043
Total assets at fair value	$	158,838	$	15,547	$	—	$	174,385