Intangible Assets

6 Months Ended

Jun. 30, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

(5) Intangible Assets

Intangible Assets Subject to Amortization

	June 30, 2020				December 31, 2019
	Gross			Net	Gross			Net
	carrying		Accumulated	carrying	carrying		Accumulated	carrying
	amount		amortization	amount	amount		amortization	amount
	amounts in thousands
Customer relationships	$	408,267	(112,192)	296,075		408,267	(95,167)	313,100
Other amortizable intangibles		145,028	(71,522)	73,506		139,721	(60,842)	78,879
Total	$	553,295	(183,714)	369,581		547,988	(156,009)	391,979

Amortization expense for intangible assets with finite useful lives was $14.0 million and $15.0 million for the three months ended June 30, 2020 and 2019, respectively. Amortization expense for intangible assets with finite useful lives was $28.0 million and $31.3 million for the six months ended June 30, 2020 and 2019, respectively. Amortization expense for amortizable intangible assets for each of the five succeeding fiscal years is estimated to be (amounts in thousands):

Remainder of 2020	$	27,713
2021	$	45,434
2022	$	39,491
2023	$	34,966
2024	$	31,081

(3)