Pension Plans and Other Postretirement Benefits (Details-5) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 330,886	$ 327,500
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	300
Equity Securities [Member] | U.S. Large Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	98,949	99,256
Equity Securities [Member] | U.S. Mid Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,446	22,926
Equity Securities [Member] | U.S. Small Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27,561	29,353
Equity Securities [Member] | International Blend [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	55,948	47,650
Fixed Income Securities [Member] | Short-Term Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,388	3,776
Fixed Income Securities [Member] | High Yield Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	16,225	15,492
Fixed Income Securities [Member] | Long Duration Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	73,112	79,603
Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27,231	23,480
Insurance Continuance Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,518	1,518
Fixed Rate Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,208	4,446
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	300	0
Level 1 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	300
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	0
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	297,629	298,056
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	98,949	99,256
Level 2 [Member] | Equity Securities [Member] | U.S. Mid Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,446	22,926
Level 2 [Member] | Equity Securities [Member] | U.S. Small Cap [Memeber]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	27,561	29,353
Level 2 [Member] | Equity Securities [Member] | International Blend [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	55,948	47,650
Level 2 [Member] | Fixed Income Securities [Member] | Short-Term Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,388	3,776
Level 2 [Member] | Fixed Income Securities [Member] | High Yield Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	16,225	15,492
Level 2 [Member] | Fixed Income Securities [Member] | Long Duration Bond [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	73,112	79,603
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	0
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32,957	29,444
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	27,231	23,480	$ 19,628
Level 3 [Member] | Insurance Continuance Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,518	1,518	1,428
Level 3 [Member] | Fixed Rate Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 4,208	$ 4,446	$ 0