Consolidated Businesses - Allocations of Purchase Price to Identified Intangible Assets and Tangible Assets and Liabilities (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016	Oct. 31, 2016	Sep. 16, 2016	Jan. 22, 2016
Net assets acquired:
Goodwill	$ 231,424	$ 231,787
ErgoAdvocate, E3 Solutions, and SAS | Non-compete agreements
Business Acquisition [Line Items]
Finite intangible assets, useful life	5 years
ErgoAdvocate
Net assets acquired:
Goodwill					$ 155
Deferred revenue					0
Other net assets (liabilities)					0
Total net assets acquired					1,250
ErgoAdvocate | Customer lists
Net assets acquired:
Intangible assets					26
ErgoAdvocate | Trademarks, tradenames, and domain names
Net assets acquired:
Intangible assets					0
ErgoAdvocate | Technology
Net assets acquired:
Intangible assets					1,069
ErgoAdvocate | Non-compete agreements
Net assets acquired:
Intangible assets					$ 0
E3 Solutions
Net assets acquired:
Goodwill				$ 1,074
Deferred revenue				0
Other net assets (liabilities)				0
Total net assets acquired				3,000
E3 Solutions | Customer lists
Net assets acquired:
Intangible assets				28
E3 Solutions | Trademarks, tradenames, and domain names
Net assets acquired:
Intangible assets				6
E3 Solutions | Technology
Net assets acquired:
Intangible assets				1,822
E3 Solutions | Non-compete agreements
Net assets acquired:
Intangible assets				$ 70
SAS
Net assets acquired:
Goodwill			$ 9,736
Deferred revenue			(320)
Other net assets (liabilities)			(397)
Total net assets acquired			11,749
SAS | Customer lists
Net assets acquired:
Intangible assets			2,153
SAS | Trademarks, tradenames, and domain names
Net assets acquired:
Intangible assets			0
SAS | Technology
Net assets acquired:
Intangible assets			344
SAS | Non-compete agreements
Net assets acquired:
Intangible assets			$ 233
Minimum | Technology
Business Acquisition [Line Items]
Finite intangible assets, useful life	5 years	5 years
Minimum | Non-compete agreements
Business Acquisition [Line Items]
Finite intangible assets, useful life	3 years	3 years
Minimum | ErgoAdvocate, E3 Solutions, and SAS | Customer lists
Business Acquisition [Line Items]
Finite intangible assets, useful life	5 years
Minimum | ErgoAdvocate, E3 Solutions, and SAS | Trademarks, tradenames, and domain names
Business Acquisition [Line Items]
Finite intangible assets, useful life	5 years
Minimum | ErgoAdvocate, E3 Solutions, and SAS | Technology
Business Acquisition [Line Items]
Finite intangible assets, useful life	7 years
Maximum | Trademarks, tradenames, and domain names
Business Acquisition [Line Items]
Finite intangible assets, useful life	11 years
Maximum | Technology
Business Acquisition [Line Items]
Finite intangible assets, useful life	9 years	9 years
Maximum | Non-compete agreements
Business Acquisition [Line Items]
Finite intangible assets, useful life	5 years	5 years
Maximum | ErgoAdvocate, E3 Solutions, and SAS | Customer lists
Business Acquisition [Line Items]
Finite intangible assets, useful life	11 years
Maximum | ErgoAdvocate, E3 Solutions, and SAS | Technology
Business Acquisition [Line Items]
Finite intangible assets, useful life	9 years