Goodwill and Other Intangible Assets:

The following table shows changes in the carrying amount of Goodwill for the years ended December 31, 2018, 2017, and 2016 (in millions):



	Inpatient Rehabilitation		Home Health and Hospice			Consolidated
Goodwill as of December 31, 2015	$	1,133.1	$	757.0		$	1,890.1
Acquisitions	8.9		42.5			51.4
Divestiture of pediatric home health services	—		(14.3		)	(14.3		)
Goodwill as of December 31, 2016	1,142.0		785.2			1,927.2
Acquisitions	24.0		21.4			45.4
Goodwill as of December 31, 2017	1,166.0		806.6			1,972.6
Acquisitions	23.2		105.0			128.2
Goodwill as of December 31, 2018	$	1,189.2	$	911.6		$	2,100.8

Goodwill increased in 2016 as a result of our acquisitions of inpatient and home health and hospice operations offset by the divestiture of our pediatric home health assets to Thrive Skilled Pediatric Care in November 2016 for approximately $21 million. We recorded a $3.3 million gain as part of Other operating expenses in our consolidated statements of operations during the year ended December 31, 2016. Goodwill increased in 2017 as a result of our acquisitions of inpatient and home health operations. Goodwill increased in 2018 as a result of our acquisitions of Camellia and other inpatient and home health and hospice operations. See Note 2, Business Combinations.

We performed impairment reviews as of October 1, 2018, 2017, and 2016 and concluded no Goodwill impairment existed. As of December 31, 2018, we had no accumulated impairment losses related to Goodwill.

The following table provides information regarding our other intangible assets (in millions):



	Gross Carrying Amount		Accumulated Amortization			Net
Certificates of need:
2018	$	148.3	$	(28.2	)	$	120.1
2017	113.7		(19.5		)	94.2
Licenses:
2018	$	169.1	$	(82.2	)	$	86.9
2017	146.0		(71.6		)	74.4
Noncompete agreements:
2018	$	65.6	$	(58.6	)	$	7.0
2017	63.5		(55.4		)	8.1
Trade name - Encompass:
2018	$	135.2	$	—		$	135.2
2017	135.2		—			135.2
Trade names - all other:
2018	$	38.9	$	(19.4	)	$	19.5
2017	35.1		(16.4		)	18.7
Internal-use software:
2018	$	161.3	$	(89.3	)	$	72.0
2017	201.6		(132.3		)	69.3
Market access assets:
2018	$	13.2	$	(10.5	)	$	2.7
2017	13.2		(10.0		)	3.2
Total intangible assets:
2018	$	731.6	$	(288.2	)	$	443.4
2017	708.3		(305.2		)	403.1

Amortization expense for other intangible assets is as follows (in millions):



	For the Year Ended December 31,
	2018		2017		2016
Amortization expense	$	51.4	$	49.3	$	48.5

Total estimated amortization expense for our other intangible assets for the next five years is as follows (in millions):



Year Ending December 31,	Estimated Amortization Expense
2019	$	56.9
2020	43.3
2021	35.7
2022	29.6
2023	27.0