Pension and Other Postretirement Benefits Fair Value of Plan Assets (Details) - Pension Plan [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	$ 249,326	$ 277,139
Plan Asset Receivable Or Payable Accrued Interest And Dividend Income	486	510
Plan Asset Receivable Or Payable Due From Broker Securities Sold	88	1,694
Total Pension Plan Asset Receivables	574	2,204
Plan Asset Receivable Or Payable Due From Broker Securities Purchased	562	179
Defined Benefit Plan, Fair Value of Plan Assets	249,338	279,164	$ 267,062
Domestic Large Cap Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	44,528	39,527
Domestic Small/Mid Cap Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	23,495	27,257
Foreign Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	43,548	33,590
Emerging Market Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	11,120	7,145
Fixed Income Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables		598
Government Or Credit Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	48,456	80,819
High Yield Bond Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	12,298	13,087
Emerging Market Debt [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	7,746	9,133
Real Estate Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	17,261	18,890
Absolute Return Strategy Investment Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	36,758	37,065
Real Return Strategy Investment Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables		8,308
Cash and Cash Equivalents [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	4,116	1,720
Fair Value, Inputs, Level 1 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	113,755	159,861
Fair Value, Inputs, Level 1 [Member] | Domestic Large Cap Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	44,528	39,405
Fair Value, Inputs, Level 1 [Member] | Domestic Small/Mid Cap Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	23,495	27,172
Fair Value, Inputs, Level 1 [Member] | Foreign Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	20,725	16,369
Fair Value, Inputs, Level 1 [Member] | Emerging Market Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 1 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets		0
Fair Value, Inputs, Level 1 [Member] | Government Or Credit Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	40,584
Fair Value, Inputs, Level 1 [Member] | High Yield Bond Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 1 [Member] | Emerging Market Debt [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	7,746	9,133
Fair Value, Inputs, Level 1 [Member] | Real Estate Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	17,261	18,890
Fair Value, Inputs, Level 1 [Member] | Absolute Return Strategy Investment Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 1 [Member] | Real Return Strategy Investment Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets		8,308
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 2 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	135,571	117,278
Fair Value, Inputs, Level 2 [Member] | Domestic Large Cap Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	122
Fair Value, Inputs, Level 2 [Member] | Domestic Small/Mid Cap Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	85
Fair Value, Inputs, Level 2 [Member] | Foreign Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	22,823	17,221
Fair Value, Inputs, Level 2 [Member] | Emerging Market Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	11,120	7,145
Fair Value, Inputs, Level 2 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets		598
Fair Value, Inputs, Level 2 [Member] | Government Or Credit Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	48,456	40,235
Fair Value, Inputs, Level 2 [Member] | High Yield Bond Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	12,298	13,087
Fair Value, Inputs, Level 2 [Member] | Emerging Market Debt [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 2 [Member] | Real Estate Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 2 [Member] | Absolute Return Strategy Investment Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	36,758	37,065
Fair Value, Inputs, Level 2 [Member] | Real Return Strategy Investment Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets		0
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	4,116	1,720
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Total Pension Asset Investments Net Of Receivables And Payables	0	0
Fair Value, Inputs, Level 3 [Member] | Domestic Large Cap Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | Domestic Small/Mid Cap Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | Foreign Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | Emerging Market Equity Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | Fixed Income Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets		0
Fair Value, Inputs, Level 3 [Member] | Government Or Credit Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | High Yield Bond Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | Emerging Market Debt [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | Real Estate Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | Absolute Return Strategy Investment Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	0	0
Fair Value, Inputs, Level 3 [Member] | Real Return Strategy Investment Securities [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets		0
Fair Value, Inputs, Level 3 [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Defined Benefit Plan, Fair Value of Plan Assets	$ 0	$ 0