Other intangible assets

6 Months Ended

Jun. 30, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Other intangible assets consist of the following as of June 30, 2017:



	Favorable lease assets	Internet sites	Trade names	Total
	$'000	$'000	$'000	$'000

Carrying amount:
Balance at January 1, 2017	8,501	1,658	7,579	17,738
Additions	—	—	6,100	6,100
Foreign currency translation adjustment	94	97	124	315

Balance at June 30, 2017	8,595	1,755	13,803	24,153

Accumulated amortization:
Balance at January 1, 2017	2,636	1,225		3,861
Charge for the period	184	84		268
Foreign currency translation adjustment	33	72		105

Balance at June 30, 2017	2,853	1,381		4,234

Net book value:
At June 30, 2017	5,742	374	13,803	19,919

At December 31, 2016	5,865	433	7,579	13,877

Favorable lease intangible assets are amortized over the terms of the leases, which are between 19 and 60 years. Internet sites are amortized over a period of five to ten years. Trade names have an indefinite life and therefore are not amortized, but are assessed for impairment annually or when events indicate that impairment may have occurred.

In the six months ended June 30, 2017, trade name additions of $6,100,000 were recognized on acquisition of Cap Juluca. See Note 3.

Amortization expense for the three and six months ended June 30, 2017 was $135,000 (June 30, 2016 - $148,000) and $268,000 (June 30, 2016 - $271,000). Estimated total amortization expense for the remainder of the year ending December 31, 2017 is $268,000 and for each of the years ending December 31, 2018 to December 31, 2021 is $536,000.