Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of carrying amount of goodwill

The following table shows changes in the carrying amounts of goodwill by reporting unit for the years ended December 31, 2016 and 2017:

	Long Term Acute Care		Inpatient Rehabilitation		Specialty Hospitals			Outpatient Rehabilitation			Concentra		Total
	(in thousands)
Balance as of January 1, 2016	$	—	$	—	$	1,357,379		$	306,595		$	650,650	$	2,314,624
Acquired	—		—		96,785			345,355			4,562		446,702
Measurement period adjustment	—		—		—			—			4,825		4,825
Sold	—		—		(6,758		)	(8,393		)	—		(15,151		)
Balance as of December 31, 2016	$	—	$	—	$	1,447,406		$	643,557		$	660,037	$	2,751,000
Acquired	—		12,887		797			3,797			14,505		31,986
Measurement period adjustment	—		—		(342		)	168			—		(174		)
Reorganization of reporting units	1,045,220		402,641		(1,447,861		)	—			—		—
Balance as of December 31, 2017	$	1,045,220	$	415,528	$	—		$	647,522		$	674,542	$	2,782,812

Schedule of carrying value and amortization of identifiable intangible assets and liabilities

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

	December 31,
	2016							2017
	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
	(in thousands)
Identifiable intangibles—Indefinite lived assets:
Trademarks	$	166,698	$	—		$	166,698	$	166,698	$	—		$	166,698
Certificates of need	17,026		—			17,026		19,155		—			19,155
Accreditations	2,235		—			2,235		1,895		—			1,895
Identifiable intangibles—Finite lived assets:
Customer relationships	142,198		(23,185		)	119,013		143,953		(38,281		)	105,672
Favorable leasehold interests	13,089		(2,317		)	10,772		13,295		(4,319		)	8,976
Non-compete agreements	26,655		(1,837		)	24,818		28,023		(3,900		)	24,123
Total identifiable intangible assets	$	367,901	$	(27,339	)	$	340,562	$	373,019	$	(46,500	)	$	326,519

Schedule of amortization expense for customer relationships and non-compete agreements

Estimated amortization expense of the Company’s customer relationships and non-compete agreements for each of the five succeeding years is as follows:

	2018		2019		2020		2021		2022
	(in thousands
Amortization expense	$	16,831	$	16,802	$	16,647	$	16,483	$	16,332