Other Income (Loss), Net - Additional Information (Detail) - Anthem - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	May 08, 2017	Mar. 31, 2017	Mar. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales / distributions of ownership interests		$ 1,000	$ 30
Gain recognized from investment		$ 1,000	$ 30
Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sales / distributions of ownership interests	$ 1,400