Retirement Plans - Assumptions Used to Determine the Net Periodic Benefit Cost and Benefit Obligations (Details) - Pension Plans, Defined Benefit [Member]	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Discount rate for net periodic pension cost	3.90%	4.70%	3.75%
Discount rate for benefit obligations	4.30%	3.90%	4.70%
Expected long-term return of plan assets	7.50%	8.00%	8.00%