Intangible Assets

Intangible assets consist of finite and indefinite life assets and are reported within Other assets in our consolidated balance sheets.

The following is a summary of our intangible assets as of December 31, 2018 (in thousands, except weighted average amortization period):



	As of December 31, 2018
	Remaining Weighted Average Amortization Period (Years)	Gross Carrying Value		Accumulated Amortization		Net Carrying Value
Finite-life intangible assets:
Customer relationships	14.8	$	97,400	$	1,082	$	96,318
Galapagos operating licenses	25.8	47,669		4,206		43,463
Other finite-life intangible assets	1.8	11,560		963		10,597
Total finite-life intangible assets		156,629		6,251		150,378
Indefinite-life intangible assets		351,725		—		351,725
Total intangible assets, net		$	508,354	$	6,251	$	502,103

As of December 31, 2017, finite-life intangible assets had a gross carrying amount and accumulated amortization amount of $11.6 million and $3.7 million, respectively, consisting of operating licenses to operate in the Galapagos Islands. As of December 31, 2017, the remaining weighted average remaining life of these licenses was approximately 26.6 years. The carrying amount of indefinite-life intangible assets was not material as of December 31, 2017.

As of December 31, 2018, intangible assets, net include intangible assets acquired in the Silversea Cruises acquisition, which were recorded at fair value at acquisition date as follows:



	Fair Value at Acquisition Date (in thousands)		Weighted Average Amortization Period (Years)
Silversea Cruises trade name	$	349,500	Indefinite-life
Customer relationships	97,400		15
Galapagos operating license	36,100		26
Other finite-life intangible assets	11,560		2
Total intangible assets	$	494,560

Amortization expense for finite-life intangible assets was immaterial to our consolidated financial statements for the years ended December 31, 2018, 2017 and 2016.

The estimated future amortization for finite-life intangible assets for each of the next five years is as follows (in thousands):



Year
2019	$	13,959
2020	$	12,995
2021	$	8,179
2022	$	8,179
2023	$	8,179