Goodwill and Other Intangible Assets

3 Months Ended

Mar. 31, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

The carrying amount of goodwill, by operating segment is as follows:



(In thousands)	National Networks			International and Other			Total
December 31, 2018	$	238,431		$	559,606		$	798,037
Puchase accounting adjustments	—			(1,748		)	(1,748		)
Amortization of "second component" goodwill	(332		)	—			(332		)
Foreign currency translation	—			1,836			1,836
March 31, 2019	$	238,099		$	559,694		$	797,793

Purchase accounting adjustments relate to the acquisition of RLJE (see Note 5).

The reduction of $0.3 million in the carrying amount of goodwill for the National Networks is due to the realization of a tax benefit for the amortization of "second component" goodwill at SundanceTV. Second component goodwill is the amount of tax deductible goodwill in excess of goodwill for financial reporting purposes. In accordance with the authoritative guidance at the time of the SundanceTV acquisition, the tax benefits associated with this excess are applied to first reduce the amount of goodwill, and then other intangible assets for financial reporting purposes, if and when such tax benefits are realized in the Company's tax returns.

The following tables summarize information relating to the Company's identifiable intangible assets:



(In thousands)	March 31, 2019
(In thousands)	Gross		Accumulated Amortization			Net		Estimated Useful Lives
Amortizable intangible assets:
Affiliate and customer relationships	$	615,628	$	(205,195	)	$	410,433	6 to 25 years
Advertiser relationships	46,282		(18,665		)	27,617		11 years
Trade names	124,453		(19,756		)	104,697		3 to 20 years
Other amortizable intangible assets	13,428		(6,548		)	6,880		5 to 15 years
Total amortizable intangible assets	799,791		(250,164		)	549,627
Indefinite-lived intangible assets:
Trademarks	19,900		—			19,900
Total intangible assets	$	819,691	$	(250,164	)	$	569,527
(In thousands)	December 31, 2018
(In thousands)	Gross		Accumulated Amortization			Net
Amortizable intangible assets:
Affiliate and customer relationships	$	620,771	$	(198,500	)	$	422,271
Advertiser relationships	46,282		(17,613		)	28,669
Trade names	118,772		(17,971		)	100,801
Other amortizable intangible assets	13,643		(6,377		)	7,266
Total amortizable intangible assets	799,468		(240,461		)	559,007
Indefinite-lived intangible assets:
Trademarks	19,900		—			19,900
Total intangible assets	$	819,368	$	(240,461	)	$	578,907

Aggregate amortization expense for amortizable intangible assets for the three months ended March 31, 2019 and 2018 was $10.3 million and $9.3 million, respectively. Estimated aggregate amortization expense for intangible assets subject to amortization for each of the following five years is:



(In thousands)
Years Ending December 31,
2019	$	44,784
2020	47,216
2021	46,422
2022	46,159
2023	46,076