6. 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 29,		Impairment		Amortization		March 29,
(in thousands)	2019		Charges		Expense		2020
Intangible assets subject to amortization	$	838,336	$	—	$	—	$	838,336
Accumulated amortization		(831,878)		—		(224)		(832,102)
		6,458		—		(224)		6,234
Mastheads		62,795		(4,769)		—		58,026
Goodwill		420,178		(58,993)		—		361,185
Total	$	489,431	$	(63,762)	$	(224)	$	425,445

Impairment of Goodwill and Intangible Assets

During the quarter ended March 29, 2020, we performed an interim test of impairment of goodwill and intangible newspaper mastheads due to the continuing challenging business conditions, the impact of COVID-19, 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 3) 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 $19.9 million and $39.1 million, respectively, during the quarter ended March 29, 2020. We also recorded an intangible newspaper masthead impairment charge of $4.8 million in the first quarter of 2020. 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 or intangible newspaper mastheads during the three months ended March 31, 2019.

Amortization expense with respect to intangible assets is summarized below:


	Three Months Ended
	March 29,		March 31,
(in thousands)	2020		2019
Amortization expense	$	224	$	11,801

The estimated amortization expense for the remainder of fiscal year 2020 and the five succeeding fiscal years is as follows:


	Amortization
	Expense
Year	(in thousands)
2020 (Remainder)	$	579
2021		680
2022		655
2023		667
2024		640
2025		363