Discontinued Operations - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain from sale of discontinued operations, net of tax provision	$ 0	$ 57,377,000	$ 0
Angel.Com
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operation, cash from sale		111,200,000
Discontinued operation, net cash from sale		100,700,000
Gain from sale of discontinued operations, net of tax provision		57,377,000
Discontinued operation, transaction costs		$ 10,500,000