Intangible Assets

3 Months Ended

Mar. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible assets include transportation agreements and customer relationships that represent a portion of the total purchase price of certain assets acquired from Delek in 2005, from HFC in 2008 prior to HEP becoming a consolidated VIE of HFC and from Plains in 2017.

The carrying amounts of our intangible assets are as follows:



	Useful Life	March 31, 2018		December 31, 2017
		(In thousands)
Delek transportation agreement	30 years	$	59,933	$	59,933
HFC transportation agreement	10-15 years	75,131		75,131
Customer relationships	10 years	69,282		69,282
Other		50		50
		204,396		204,396
Less accumulated amortization		78,969		74,933
		$	125,427	$	129,463

Amortization expense was $4.0 million and $1.7 million for the three months ended March 31, 2018 and 2017, respectively. We estimate amortization expense to be $14.0 million for each of the next four years and $9.8 million in 2023.

We have additional transportation agreements with HFC resulting from historical transactions consisting of pipeline, terminal and tankage assets contributed to us or acquired from HFC. These transactions occurred while we were a consolidated VIE of HFC; therefore, our basis in these agreements is zero and does not reflect a step-up in basis to fair value.