Employee Benefits (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Interest perrcentage accrued on employees account balances (in hundredths)			5.25%
Defined Benefit Plan, Interest Percentage Accrued On Employee Account Balances, Next Fiscal Year (Rate to Add to Treasury Securities Rate)	1.50%
Defined Benefit Plan Interest Percentage Accrued On Employee Account Balances, Next Fiscal Year (Minimum)	2.50%
Defined Benefit Plan Interest Percentage Accrued on Employee Account Balances, Next Fiscal Year (Maximum)	5.00%
Thrift Plan - Defined Contribution [Abstract]
Employee base compensation company match employee contributions (in hundredths)	6.00%
Employer matching rate for employee contributions minimum (in hundredths)	50.00%
Minimum years of service for employees to obtain maximum employer matching (in years)	P4Y
Employer matching rate for employee contributions maximum (in hundredths)	200.00%
Maximum years of service for employees to obtain minimum employer matching (in years)	15 years
Non-elective annual contribution for qualified employees	$ 750
Annual base employee compensation to qualify for non-elective employer contributions maximum	40,000
Defined Contribution Plan, Employer Discretionary Contribution Amount	738,000		802,000		933,000
Vesting period for employer contributions (in years)	5 years
Thrift Plan expenses	18,100,000		16,800,000		15,400,000
Incentive compensation plans [Abstract]
Charge to earnings for incentive compensation plan	151,100,000		153,900,000		117,800,000
DefinedBenefitPlanQuarterlyVariableInterestRateAccruedOnEmployeeAccountBalancesMinimum	3.07%
DefinedBenefitPlanQuarterlyVariableRateAccruedOnEmployeeAccountBalancesMaximum	3.27%
Pension Plan [Member]
Change in projected benefit obligation [Roll Forward]
Projected benefit obligation at beginning of year	48,028,000	[1],[2]	50,213,000
Interest cost	1,532,000		1,925,000
Actuarial loss	(1,543,000)		2,786,000
Benefits paid	(3,252,000)		(2,194,000)
Plan amendments	0		(4,702,000)
Projected benefit obligation at end of year	44,765,000	[1],[2]	48,028,000	[1],[2]
Change in plan assets [Roll Forward]
Plan assets at fair value at beginning of year	45,920,000		43,859,000
Actual return on plan assets	6,144,000		4,255,000
Benefits paid	(3,252,000)		(2,194,000)
Plan assets at fair value at end of year	48,812,000		45,920,000
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status of the plan	4,047,000		(2,108,000)
Components of net periodic benefit costs [Abstract]
Interest cost	1,532,000		1,925,000
Expected return on plan assets	(2,185,000)		(2,062,000)
Recognized prior service cost	(1,175,000)		0
Amortization of unrecognized net loss	3,830,000		3,461,000
Net periodic pension cost (benefit)	2,002,000		3,324,000
Weighted-average assumptions [Abstract]
Discount rate (in hundredths)	4.05%		3.36%
Expected return on plan assets (in hundredths)	6.00%		5.25%
Estimated Future Benefit Payments [Abstract]
2014	3,886,000
2015	3,713,000
2016	3,386,000
2017	3,351,000
2018	3,488,000
Thereafter	40,394,000
Total estimated future benefit payments	58,218,000
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Plan Assets, Inception to date return (in hundredths)	7.34%
Defined Benefit Plan, Plan contributions, Maximum allowed	23,000,000
Net pension costs currently in accumulated other comprehensive income to be recognized as net periodic pension cost in next fiscal year	$ 600,000
Equity Securities [Member] | Pension Plan [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of equities included in portfolio mix of fund used for defined benefit plan (in hundredths)	60.00%
Bonds [Member] | Pension Plan [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Percentage of equities included in portfolio mix of fund used for defined benefit plan (in hundredths)	40.00%

[1] Projected benefit obligation is based on January 1 measurement date.

[2] Projected benefit obligation equals accumulated benefit obligation.