Employee Benefit Plans Schedule of Defined Benefit Plan Activity (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Amounts recognized in the consolidated balance sheets:
Prepaid pension costs	$ 26,080	$ 12,870
Non-current employee benefits	(47,917)	(45,860)
Pension Plans [Member]
Change in benefit obligation:
Benefit obligation at January 1	(153,716)	(151,008)
Service cost	(1,170)	(1,275)	(1,422)
Interest cost	(5,518)	(6,513)	(7,481)
Plan settlement	1,819	0
Benefits paid	10,510	12,813
Expenses paid	350	308
Actuarial (gain) loss	(3,186)	(8,041)
Benefit obligation at December 31	(150,911)	(153,716)	(151,008)
Change in plan assets:
Fair value of plan assets at January 1	128,060	122,012
Actual return on plan assets	19,482	15,656
Plan settlement	(1,819)	0
Expenses paid	(350)	(308)
Contributions	2,173	3,513
Benefits paid	(10,510)	(12,813)
Fair value of plan assets at December 31	137,036	128,060	122,012
Funded status at December 31	(13,875)	(25,656)
Amounts recognized in the consolidated balance sheets:
Prepaid pension costs	26,080	12,870
Other accrued liabilities	(342)	(2,161)
Non-current employee benefits	(39,613)	(36,365)
Net amounts recognized	(13,875)	(25,656)
Other Postretirement Benefits [Member]
Change in benefit obligation:
Benefit obligation at January 1	(10,158)	(9,635)
Service cost	(16)	(14)	(13)
Interest cost	(418)	(465)	(500)
Plan settlement	0	0
Benefits paid	560	512
Expenses paid	0	0
Actuarial (gain) loss	1,133	(556)
Benefit obligation at December 31	(8,899)	(10,158)	(9,635)
Change in plan assets:
Fair value of plan assets at January 1	0	0
Actual return on plan assets	0	0
Plan settlement	0	0
Expenses paid	0	0
Contributions	560	512
Benefits paid	(560)	(512)
Fair value of plan assets at December 31	0	0	0
Funded status at December 31	(8,899)	(10,158)
Amounts recognized in the consolidated balance sheets:
Prepaid pension costs	0	0
Other accrued liabilities	(597)	(663)
Non-current employee benefits	(8,304)	(9,495)
Net amounts recognized	$ (8,901)	$ (10,158)