Pension Plans and Other Postretirement Benefits (Details-5) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 327,500	$ 315,000
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		5,109
Equity Securities [Member] | U.S. Large Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	99,256	96,258
Equity Securities [Member] | U.S. Mid Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,926	22,741
Equity Securities [Member] | U.S. Small Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29,353	28,854
Equity Securities [Member] | International Blend [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	47,650	54,873
Fixed Income Securities [Member] | Short-Term Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,776	4,789
Fixed Income Securities [Member] | High Yield Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15,492	15,127
Fixed Income Securities [Member] | Long Duration Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	79,603	66,193
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	23,480	19,628
Insurance Continuance Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,518	1,428
Fixed Rate Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,446
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	5,109
Level 1 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		5,109
Level 1 [Member] | Equity Securities [Member] | U.S. Large Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Equity Securities [Member] | U.S. Mid Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Equity Securities [Member] | U.S. Small Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Equity Securities [Member] | International Blend [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Fixed Income Securities [Member] | Short-Term Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Fixed Income Securities [Member] | High Yield Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Fixed Income Securities [Member] | Long Duration Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Insurance Continuance Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member] | Fixed Rate Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	298,056	288,835
Level 2 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Level 2 [Member] | Equity Securities [Member] | U.S. Large Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	99,256	96,258
Level 2 [Member] | Equity Securities [Member] | U.S. Mid Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,926	22,741
Level 2 [Member] | Equity Securities [Member] | U.S. Small Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29,353	28,854
Level 2 [Member] | Equity Securities [Member] | International Blend [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	47,650	54,873
Level 2 [Member] | Fixed Income Securities [Member] | Short-Term Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,776	4,789
Level 2 [Member] | Fixed Income Securities [Member] | High Yield Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15,492	15,127
Level 2 [Member] | Fixed Income Securities [Member] | Long Duration Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	79,603	66,193
Level 2 [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Insurance Continuance Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Fixed Rate Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	29,444	21,056
Level 3 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Level 3 [Member] | Equity Securities [Member] | U.S. Large Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Equity Securities [Member] | U.S. Mid Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Equity Securities [Member] | U.S. Small Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Equity Securities [Member] | International Blend [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Fixed Income Securities [Member] | Short-Term Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Fixed Income Securities [Member] | High Yield Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Fixed Income Securities [Member] | Long Duration Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	23,480	19,628	17,141
Level 3 [Member] | Insurance Continuance Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,518	1,428	1,466
Level 3 [Member] | Fixed Rate Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 4,446	$ 0	$ 0