Intangible Assets

3 Months Ended

Mar. 31, 2016

Intangible Assets, Net (Excluding Goodwill) [Abstract]

Intangible Assets

Intangible Assets

The following table summarizes the components of our intangible assets at the dates indicated:

	March 31, 2016						December 31, 2015
	Gross Carrying Amount		Accumulated Amortization		Carrying Value		Gross Carrying Amount		Accumulated Amortization		Carrying Value
Refinery Services:
Customer relationships	$	94,654	$	87,153	$	7,501	$	94,654	$	86,285	$	8,369
Licensing agreements	38,678		32,322		6,356		38,678		31,694		6,984
Segment total	133,332		119,475		13,857		133,332		117,979		15,353
Supply & Logistics:
Customer relationships	35,430		32,452		2,978		35,430		32,044		3,386
Intangibles associated with lease	13,260		4,104		9,156		13,260		3,986		9,274
Segment total	48,690		36,556		12,134		48,690		36,030		12,660
Marine contract intangibles	27,000		2,250		24,750		27,000		900		26,100
Offshore pipeline contract intangibles	158,101		5,547		152,554		158,101		3,467		154,634
Other	26,151		8,660		17,491		22,819		8,120		14,699
Total	$	393,274	$	172,488	$	220,786	$	389,942	$	166,496	$	223,446

Our amortization of intangible assets for the periods presented was as follows:

	Three Months Ended March 31,
	2016		2015
Amortization of intangible assets	$	5,992	$	4,037

We estimate that our amortization expense for the next five years will be as follows:

Remainder of	2016	$	18,322
	2017	$	23,273
	2018	$	21,157
	2019	$	16,830
	2020	$	15,929