Acquisitions - Additional Information (Detail) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) Center Business	Dec. 31, 2018 USD ($) Center Business	Dec. 31, 2017 USD ($) Center Business
Business Acquisition [Line Items]
Business combination, contingent consideration, liability		$ 13,870	$ 0	$ 0
Contingent consideration payment term		3 years
Goodwill		$ 1,412,873	1,347,611	1,306,792
Payment for contingent consideration		4,200	2,965	185
Payments and settlements for acquisitions—net of cash acquired		$ 53,425	$ 67,111	$ 21,484
IRELAND
Business Acquisition [Line Items]
Number of properties disposed | Center				3
Loss on disposal				$ 3,700
Income (loss) from subsidiaries, tax expense (benefit)				$ 7,000
Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Number of businesses acquired | Business		8	7	7
Cash consideration to acquire business, gross		$ 53,300		$ 21,500
Cash acquired		1,200	$ 4,200	300
Business combination, contingent consideration, liability		700		200
Contingent consideration, maximum value		20,000
Fair value of contingent consideration		13,900
Goodwill			60,300	14,300
Goodwill, expected tax deductible amount			13,900
Intangible assets consisting of customer relationships and trade names		14,600		2,300
Fixed assets and technology acquired		3,100
Deferred tax liabilities		(1,900)	(1,900)
Revenue contributed by acquiree		18,100
Payment for contingent consideration		$ 4,200
Payments and settlements for acquisitions—net of cash acquired			66,800
Contingent consideration			5,400
Fixed assets acquired			8,300
Net identifiable assets acquired and liabilities assumed			$ 1,100	(1,300)
Buildings acquired				7,300
Deferred tax liabilities				$ (600)
Series of Individually Immaterial Business Acquisitions | UNITED STATES
Business Acquisition [Line Items]
Number of centers acquired | Center		3	6	3
Series of Individually Immaterial Business Acquisitions | NETHERLANDS
Business Acquisition [Line Items]
Number of centers acquired | Center		4	10	10
Series of Individually Immaterial Business Acquisitions | United Kingdom
Business Acquisition [Line Items]
Number of centers acquired | Center		1	20	1
Series of Individually Immaterial Business Acquisitions | Maximum
Business Acquisition [Line Items]
Intangible asset useful life				5 years
Conchord Limited Asquith
Business Acquisition [Line Items]
Payment for contingent consideration			$ 3,000
Payments contingent consideration			3,100
Customer Relationships | Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Intangible assets consisting of customer relationships and trade names			$ 8,600
Intangible asset useful life		5 years
Customer Relationships | Series of Individually Immaterial Business Acquisitions | Minimum
Business Acquisition [Line Items]
Intangible asset useful life			2 years	3 years
Customer Relationships | Series of Individually Immaterial Business Acquisitions | Maximum
Business Acquisition [Line Items]
Intangible asset useful life			5 years
Prior Year Series of Individually Immaterial Business Acquisitions | Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Payment for contingent consideration		$ 3,500
Prior Periods Series of Individually Immaterial Business Acquisitions | Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Payment for contingent consideration	$ 700
Back-Up Care Services | Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Goodwill		25,400
Educational advisory services | Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Goodwill		14,000
Full service center-based child care | IRELAND
Business Acquisition [Line Items]
Loss on disposal				$ (3,700)
Full service center-based child care | Series of Individually Immaterial Business Acquisitions
Business Acquisition [Line Items]
Goodwill		15,200
Goodwill, expected tax deductible amount		$ 3,900