NET EARNINGS PER LIMITED PARTNER UNIT (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended					12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2013
NET EARNINGS PER LIMITED PARTNER UNIT
Net earnings	$ 9,238				$ 11,538	$ 34,726
Less:
Distributions payable on behalf of incentive distribution rights	(1,603)				(1,154)
Distributions payable on behalf of general partner interest	(217)				(189)
Earnings allocable to general partner interest less than (in excess of) distributions payable to general partner interest	64				(19)
Earnings allocable to general partner interest including incentive distribution rights	(1,756)				(1,362)
Net earnings allocable to limited partners	7,482				10,176
Less distribution payable on behalf of unvested long-term incentive plan grants	(10)				(16)
Net earnings allocable to limited partners for calculating net earnings per limited partner unit	$ 7,472				$ 10,160
Basic weighted average units	16,103				14,438
Net earnings per limited partner unit-basic (in dollars per unit)	$ 0.46				$ 0.70
Diluted weighted average units	16,103				14,438
Net earnings per limited partner unit-diluted (in dollars per unit)	$ 0.46				$ 0.70
Period for declaration of distribution, maximum	45 days
Distribution declared per common unit
Distribution declared per common unit (in dollars per unit)	$ 0.66	$ 0.65	$ 0.65	$ 0.65	$ 0.64