Intangible Assets

3 Months Ended

Mar. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill

The following table shows changes in the carrying amounts of goodwill by reporting unit for the three months ended March 31, 2020:



	Critical Illness Recovery Hospital		Rehabilitation Hospital		Outpatient Rehabilitation			Concentra			Total
	(in thousands)
Balance as of December 31, 2019	$	1,078,804	$	430,900	$	649,763		$	1,232,488		$	3,391,955
Acquired	—		—		610			4,567			5,177
Sold	—		—		(6,034		)	—			(6,034		)
Measurement period adjustment	—		—		—			(20		)	(20		)
Balance as of March 31, 2020	$	1,078,804	$	430,900	$	644,339		$	1,237,035		$	3,391,078

Identifiable Intangible Assets

The following table provides the gross carrying amounts, accumulated amortization, and net carrying amounts for the Company’s identifiable intangible assets:



	December 31, 2019							March 31, 2020
	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
	(in thousands)
Indefinite-lived intangible assets:
Trademarks	$	166,698	$	—		$	166,698	$	166,698	$	—		$	166,698
Certificates of need	17,157		—			17,157		18,348		—			18,348
Accreditations	1,874		—			1,874		1,874		—			1,874
Finite-lived intangible assets:
Trademarks	5,000		(5,000		)	—		5,000		(5,000		)	—
Customer relationships	287,373		(87,346		)	200,027		288,963		(93,814		)	195,149
Non-compete agreements	32,114		(8,802		)	23,312		32,845		(9,540		)	23,305
Total identifiable intangible assets	$	510,216	$	(101,148	)	$	409,068	$	513,728	$	(108,354	)	$	405,374

The Company’s accreditations and indefinite-lived trademarks have renewal terms and the costs to renew these intangible assets are expensed as incurred. At March 31, 2020, the accreditations and indefinite-lived trademarks have a weighted average time until next renewal of 1.5 years and 6.9 years, respectively.

The Company’s finite-lived intangible assets amortize over their estimated useful lives. Amortization expense was $7.1 million and $6.9 million for the three months ended March 31, 2019 and 2020, respectively.