Pension and Other Post Retirement Benefit Plans - Schedule of Plan Assets by Level (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 83,557	$ 71,396	$ 77,139
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	64,064	52,433
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3,778	1,608
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate Bonds and Notes
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,646	9,113
Quoted Prices in Active Markets for Identical Assets (Level 1) | Common Stock
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	2,278	1,538
Quoted Prices in Active Markets for Identical Assets (Level 1) | Taxable Bond
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	7,974	4,536
Quoted Prices in Active Markets for Identical Assets (Level 1) | Large Cap Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	19,611	18,528
Quoted Prices in Active Markets for Identical Assets (Level 1) | Mid Cap Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,304	8,537
Quoted Prices in Active Markets for Identical Assets (Level 1) | Small Cap Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4,680	3,578
Quoted Prices in Active Markets for Identical Assets (Level 1) | International Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3,093	3,353
Quoted Prices in Active Markets for Identical Assets (Level 1) | Specialty Alternative Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,700	1,642
Significant Other Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	19,493	18,963
Significant Other Observable Inputs (Level 2) | Government Agency and Municipal Bonds and Notes
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	6,855	6,993
Significant Other Observable Inputs (Level 2) | Certificates of Deposit
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,268	1,511
Significant Other Observable Inputs (Level 2) | Common Bond Fund
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4,744	4,647
Significant Other Observable Inputs (Level 2) | Common Equity Fund
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	6,626	5,812
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets
Fair Value
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	83,557	71,396
Fair Value | Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3,778	1,608
Fair Value | Corporate Bonds and Notes
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,646	9,113
Fair Value | Government Agency and Municipal Bonds and Notes
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	6,855	6,993
Fair Value | Certificates of Deposit
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	1,268	1,511
Fair Value | Common Stock
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	2,278	1,538
Fair Value | Common Bond Fund
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4,744	4,647
Fair Value | Common Equity Fund
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	6,626	5,812
Fair Value | Taxable Bond
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	7,974	4,536
Fair Value | Large Cap Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	19,611	18,528
Fair Value | Mid Cap Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	10,304	8,537
Fair Value | Small Cap Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	4,680	3,578
Fair Value | International Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	3,093	3,353
Fair Value | Specialty Alternative Equity
Defined Benefit Plan Disclosure [Line Items]
Fair Value of Plan Assets	$ 1,700	$ 1,642