Pension Plan and Employee Benefits, Fair Value of Pension Plan Assets (Details) (Pension Benefits [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 381,771	$ 341,892
Interest Accrual	2,784	2,149
Total net assets	384,555	344,041	312,395
Cash and cash equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,942	6,336
Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17,918	16,319
Preferred Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	939	379
Obligations of U.S. Government and U.S. Government Agencies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	41,413	32,734
Mutual funds, Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	54,609	54,198
Mutual funds, International [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26,254	25,042
Common/collective trust fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42,078	39,943
Real estate funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17,928	17,341
Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,740	2,587
Corporate debt [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	172,950	147,013
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	99,720	95,938
Level 1 [Member] | Cash and cash equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17,918	16,319
Level 1 [Member] | Preferred Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	939	379
Level 1 [Member] | Obligations of U.S. Government and U.S. Government Agencies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Mutual funds, Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	54,609	54,198
Level 1 [Member] | Mutual funds, International [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26,254	25,042
Level 1 [Member] | Common/collective trust fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Real estate funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Corporate debt [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	262,383	226,026
Level 2 [Member] | Cash and cash equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,942	6,336
Level 2 [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Preferred Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Obligations of U.S. Government and U.S. Government Agencies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	41,413	32,734
Level 2 [Member] | Mutual funds, Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Mutual funds, International [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Common/collective trust fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42,078	39,943
Level 2 [Member] | Real estate funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Corporate debt [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	172,950	147,013
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	19,668	19,928
Level 3 [Member] | Cash and cash equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Preferred Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Obligations of U.S. Government and U.S. Government Agencies [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Mutual funds, Domestic [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Mutual funds, International [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Common/collective trust fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Real estate funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	17,928	17,341
Level 3 [Member] | Hedge Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,740	2,587
Level 3 [Member] | Corporate debt [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0