Retirement Plan (Changes in Benefit Obligation and Plan Assets) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension plan's benefit obligation - beginning of year	$ 15,715	$ 26,797
Defined Benefit Plan, Service Cost	895	1,112	1,892
Interest cost	638	665	3,519
Defined Benefit Plan, Contributions by Plan Participants	573	564
Defined Benefit Plan, Plan Amendments	3,383	(820)
Benefits paid	1,533	1,585
Actuarial loss	3,962	(2,391)
Settlements paid	0	8,627
Pension plan's benefit obligation - end of year	23,633	15,715	26,797
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets - beginning of year	0	0
Benefits paid	1,533	1,585
Employer contributions	960	9,648
Defined Benefit Plan, Contributions by Plan Participants	573	564
Settlements paid	0	8,627
Fair value of plan assets - end of year	0	0	0
Defined Benefit Plan, Funded Status of Plan	(23,633)	(15,715)
Pension and Other Postretirement Defined Benefit Plans, Liabilities	(23,633)	(15,715)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	(5,074)	(1,022)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	39,419	47,098
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	34,345	46,076
Retirement Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Pension plan's benefit obligation - beginning of year		95,485
Interest cost		1,797
Benefits paid		(3,957)
Actuarial loss		2,981
Settlements paid		(96,306)
Pension plan's benefit obligation - end of year		0
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets - beginning of year		77,757
Defined Benefit Plan, Actual Return on Plan Assets		(219)
Benefits paid		(3,957)
Employer contributions		22,725
Settlements paid		(96,306)
Fair value of plan assets - end of year		$ 0