Employees, Retirement and Incentive Plans (Tables)

9 Months Ended

Sep. 30, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Nonvested Restricted Stock Units Activity

A summary of restricted and phantom unit activity and changes during the nine months ended September 30, 2015, is presented below:

Restricted and Phantom Units	Units		Weighted Average Grant-Date Fair Value
Outstanding at January 1, 2015 (nonvested)	126,077		$	33.43
Forfeited	(5,591	)	33.51
Outstanding at September 30, 2015 (nonvested)	120,486		$	33.42

Schedule of Nonvested Performance-based Units Activity

A summary of performance unit activity and changes during the nine months ended September 30, 2015, is presented below:

Performance Units	Units
Outstanding at January 1, 2015 (nonvested)	71,245
Vesting and transfer of common units to recipients	(11,436	)
Outstanding at September 30, 2015 (Nonvested)	59,809