Employee Benefit Plans (Asset Fair Value) (Details 2) (Pension Plan, USD $)	12 Months Ended
	Dec. 31, 2014 item
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	$ 31,435,000
Net accrued expenses of plan	40,000
Using Quoted Prices in Active Markets for Identical Assets (Level 1)
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	19,146,000
Using Significant Other Observable Inputs (Level 2)
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	12,090,000
Using Significant Unobservable Inputs (Level 3)
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	199,000
Cash and Cash Equivalents
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	66,000
Cash and Cash Equivalents | Using Quoted Prices in Active Markets for Identical Assets (Level 1)
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	3,000
Cash and Cash Equivalents | Using Significant Other Observable Inputs (Level 2)
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	63,000
Research equity portfolio
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	12,027,000
Number of securities	220
Research equity portfolio | Financials
Benefit Plan Disclosure
Actual plan allocation (as a percent)	19.00%
Research equity portfolio | Information Technology
Benefit Plan Disclosure
Actual plan allocation (as a percent)	18.00%
Research equity portfolio | Health Care
Benefit Plan Disclosure
Actual plan allocation (as a percent)	15.00%
Research equity portfolio | Consumer Discretionary
Benefit Plan Disclosure
Actual plan allocation (as a percent)	13.00%
Research equity portfolio | Industrials
Benefit Plan Disclosure
Actual plan allocation (as a percent)	10.00%
Research equity portfolio | Consumer Staples
Benefit Plan Disclosure
Actual plan allocation (as a percent)	10.00%
Research equity portfolio | Other
Benefit Plan Disclosure
Actual plan allocation (as a percent)	15.00%
Research equity portfolio | Using Significant Other Observable Inputs (Level 2)
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	12,027,000
International stock funds
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	10,956,000
Number of funds	3
International stock funds | Fund One
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	5,900,000
International stock funds | Fund Two
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	3,400,000
International stock funds | Fund Three
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	1,600,000
International stock funds | Financials | Fund One
Benefit Plan Disclosure
Actual plan allocation (as a percent)	27.00%
International stock funds | Financials | Fund Two
Benefit Plan Disclosure
Actual plan allocation (as a percent)	29.00%
International stock funds | Financials | Fund Three
Benefit Plan Disclosure
Actual plan allocation (as a percent)	13.00%
International stock funds | Information Technology | Fund One
Benefit Plan Disclosure
Actual plan allocation (as a percent)	16.00%
International stock funds | Information Technology | Fund Two
Benefit Plan Disclosure
Actual plan allocation (as a percent)	16.00%
International stock funds | Information Technology | Fund Three
Benefit Plan Disclosure
Actual plan allocation (as a percent)	16.00%
International stock funds | Health Care | Fund One
Benefit Plan Disclosure
Actual plan allocation (as a percent)	13.00%
International stock funds | Consumer Discretionary | Fund One
Benefit Plan Disclosure
Actual plan allocation (as a percent)	15.00%
International stock funds | Consumer Discretionary | Fund Three
Benefit Plan Disclosure
Actual plan allocation (as a percent)	13.00%
International stock funds | Industrials | Fund Three
Benefit Plan Disclosure
Actual plan allocation (as a percent)	17.00%
International stock funds | Consumer Staples | Fund Two
Benefit Plan Disclosure
Actual plan allocation (as a percent)	21.00%
International stock funds | Materials | Fund Three
Benefit Plan Disclosure
Actual plan allocation (as a percent)	11.00%
International stock funds | Other | Fund One
Benefit Plan Disclosure
Actual plan allocation (as a percent)	29.00%
International stock funds | Other | Fund Two
Benefit Plan Disclosure
Actual plan allocation (as a percent)	34.00%
International stock funds | Other | Fund Three
Benefit Plan Disclosure
Actual plan allocation (as a percent)	30.00%
International stock funds | Country | Fund Three
Benefit Plan Disclosure
Actual plan allocation (as a percent)	25.00%
International stock funds | Using Quoted Prices in Active Markets for Identical Assets (Level 1)
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	10,956,000
Short-term fund
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	1,958,000
Short-term fund | Investment Grade
Benefit Plan Disclosure
Actual plan allocation (as a percent)	52.00%
Short-term fund | Mortgage
Benefit Plan Disclosure
Actual plan allocation (as a percent)	15.00%
Short-term fund | Other
Benefit Plan Disclosure
Actual plan allocation (as a percent)	33.00%
Short-term fund | Using Quoted Prices in Active Markets for Identical Assets (Level 1)
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	1,958,000
Bond fund
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	6,229,000
Number of funds	2
Bond fund | Fund One
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	5,100,000
Bond fund | Fund One | Government-related
Benefit Plan Disclosure
Actual plan allocation (as a percent)	40.00%
Bond fund | Fund One | Mortgage
Benefit Plan Disclosure
Actual plan allocation (as a percent)	23.00%
Bond fund | Fund One | Emerging Market
Benefit Plan Disclosure
Actual plan allocation (as a percent)	17.00%
Bond fund | Fund One | Other
Benefit Plan Disclosure
Actual plan allocation (as a percent)	20.00%
Bond fund | Fund Two
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	1,100,000
Bond fund | Fund Two | Sovereign Local Currency
Benefit Plan Disclosure
Actual plan allocation (as a percent)	37.00%
Bond fund | Fund Two | Sovereign Hard Currency
Benefit Plan Disclosure
Actual plan allocation (as a percent)	33.00%
Bond fund | Fund Two | Inflation Linked
Benefit Plan Disclosure
Actual plan allocation (as a percent)	17.00%
Bond fund | Fund Two | Corporate Hard Currency
Benefit Plan Disclosure
Actual plan allocation (as a percent)	11.00%
Bond fund | Fund Two | Other
Benefit Plan Disclosure
Actual plan allocation (as a percent)	2.00%
Bond fund | Country | Fund Two
Benefit Plan Disclosure
Actual plan allocation (as a percent)	25.00%
Bond fund | Using Quoted Prices in Active Markets for Identical Assets (Level 1)
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	6,229,000
Oil and gas royalty interests
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	199,000
Oil and gas royalty interests | Using Significant Unobservable Inputs (Level 3)
Benefit Plan Disclosure
Fair value of plan assets, excluding net accrued expenses	$ 199,000
Minimum | Bond fund | Fund One
Benefit Plan Disclosure
Debt security maturity period	3 years
Maximum | Short-term fund | Non-US dollar
Benefit Plan Disclosure
Actual plan allocation (as a percent)	20.00%
Maximum | Bond fund | Fund One
Benefit Plan Disclosure
Debt security maturity period	6 years
Maximum | Bond fund | Fund One | Rated Baa
Benefit Plan Disclosure
Actual plan allocation (as a percent)	10.00%
Maximum | Bond fund | Fund One | Non-US dollar
Benefit Plan Disclosure
Actual plan allocation (as a percent)	30.00%