Employees, Retirement and Incentive Plans (Tables)

12 Months Ended

Dec. 31, 2014

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

Schedule of Nonvested Restricted Stock Units Activity

A summary of restricted unit and phantom unit activity and changes during the year ended December 31, 2014, is presented below:

Restricted and Phantom Units	Units		Weighted- Average Grant-Date Fair Value
Outstanding at January 1, 2014 (nonvested)	122,951		$	33.36
Granted	91,852		33.49
Vesting and transfer of full ownership to recipients	(80,645	)	33.22
Forfeited	(8,081	)	35.28
Outstanding at December 31, 2014 (nonvested)	126,077		$	33.43

Schedule of Nonvested Performance-based Units Activity

A summary of performance unit activity and changes during the twelve months ended December 31, 2014, is presented below:

Performance Units	Units
Outstanding at January 1, 2014 (nonvested)	75,216
Granted	13,967
Vesting and transfer of common units to recipients	(17,938	)
Outstanding at December 31, 2014 (nonvested)	71,245