5. INTANGIBLE ASSETS AND GOODWILL

Intangible assets subject to amortization (primarily advertiser lists, subscriber lists and developed technology), mastheads and goodwill consisted of the following:


	December 30,		Impairment		Amortization		September 29,
(in thousands)	2018		Charges		Expense		2019
Intangible assets subject to amortization	$	838,336	$	—	$	—	$	838,336
Accumulated amortization		(807,725)		—		(23,878)		(831,603)
		30,611		—		(23,878)		6,733
Mastheads		112,736		(37,191)		—		75,545
Goodwill		705,174		(258,079)		—		447,095
Total	$	848,521	$	(295,270)	$	(23,878)	$	529,373

Impairment of Goodwill and Intangible Assets

During the quarter ended September 29, 2019, we performed an interim testing of impairment of goodwill and intangible newspaper mastheads due to the continuing challenging business conditions and changes in our assessment of profitability in future years. The fair values of our reporting units for goodwill impairment testing and individual newspaper mastheads were estimated using the present value of expected future cash flows, using estimates, judgments and assumptions (see Note 2) that we believe were appropriate in the circumstances. As a result, we recorded impairment charges in our Western and Eastern reporting units related to goodwill of $218.7 million and $39.4 million, respectively, during the quarter ended September 29, 2019. We also recorded an intangible newspaper masthead impairment charge of $37.2 million in the third quarter of 2019. These impairments were recorded in the goodwill and other asset write-downs line item on our condensed consolidated statements of operations.

We had no impairment of goodwill during the quarter and nine months ended September 30, 2018. In 2018, we recorded intangible newspaper masthead impairment charges of $14.1 million in the third quarter of 2018 and $37.2 million for the full year ended December 30, 2018.

Amortization expense with respect to intangible assets is summarized below:


	Quarters Ended				Nine Months Ended
	September 29,		September 30,		September 29,		September 30,
(in thousands)	2019		2018		2019		2018
Amortization expense	$	276	$	11,895	$	23,878	$	35,858

The estimated amortization expense for the remainder of fiscal year 2019 and the five succeeding fiscal years is as follows:


	Amortization
	Expense
Year	(in thousands)
2019 (Remainder)	$	276
2020		803
2021		680
2022		655
2023		667
2024		640