Disposition of Business - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
	May 22, 2015	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pre-tax gain on disposal of business		$ 508,810	$ 508,810
Gain on disposal of business , after -tax		395,000	$ 395,000
Disposal Group, Not Discontinued Operations | eLong, Inc
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Percentage of ownership sold	62.40%
Consideration of business sold	$ 671,000
Pre-tax gain on disposal of business		508,810
Gain on disposal of business , after -tax		$ 395,000
Disposal Group, Not Discontinued Operations | eLong, Inc | Gain on sale of business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration of business sold, net of costs to sell	$ 666,000
Disposal Group, Not Discontinued Operations | eLong, Inc | Long-term investments and other assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Held in escrow				$ 67,000