Employee Benefit Plans (Schedule of Target Allocation of Plan Assets) (Details)	12 Months Ended
	Dec. 31, 2016
Mid-Cap Stocks [Member] | Lower Range [Member]
Target Asset Allocations
Target asset allocations	30.00%
Mid-Cap Stocks [Member] | Upper Range [Member]
Target Asset Allocations
Target asset allocations	70.00%
Fixed Income Investments [Member] | Lower Range [Member]
Target Asset Allocations
Target asset allocations	30.00%
Fixed Income Investments [Member] | Upper Range [Member]
Target Asset Allocations
Target asset allocations	70.00%
Cash [Member] | Lower Range [Member]
Target Asset Allocations
Target asset allocations	0.00%
Cash [Member] | Upper Range [Member]
Target Asset Allocations
Target asset allocations	15.00%