5. Intangible Assets

Indefinite‑life intangible assets consist primarily of gaming licenses. The table below presents the gross carrying value, accumulated amortization, and net book value of each major class of other intangible assets at March 31, 2018 and December 31, 2017:


	March 31, 2018						December 31, 2017
	(in thousands)
	Gross						Gross
	Carrying		Accumulated		Net Book		Carrying		Accumulated		Net Book
	Value		Amortization		Value		Value		Amortization		Value
Indefinite-life intangible assets	$	425,505	$	—	$	425,505	$	375,405	$	—	$	375,405
Other intangible assets		132,831		88,758		44,073		131,483		84,282		47,201
Total	$	558,336	$	88,758	$	469,578	$	506,888	$	84,282	$	422,606

Total other intangible assets increased by $47 million for the three months ended March 31, 2018 primarily due to the purchase of a Category 4 gaming license to operate up to 750 slot machines and initially up to 30 table games in York County, Pennsylvania for $50.1 million, along with the capitalization of computer software intangibles of $1.4 million, partially offset by $4.5 million in amortization of definite-lived intangible assets. Other intangible assets have a weighted average remaining amortization period of approximately 4.6 years.

The Company’s intangible asset amortization expense was $4.5 million and $5.2 million, for the three months ended March 31, 2018 and 2017, respectively.

The following table presents expected intangible asset amortization expense based on existing intangible assets as of March 31, 2018 (in thousands):


Remaining 2018	$	9,554
2019		8,949
2020		6,287
2021		3,644
2022		3,596
Thereafter		12,043
Total	$	44,073