Discontinued Operations - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended		3 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Mar. 31, 2013 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
Discontinued operation, gain on sale	0	0	57,377,000	0	57,400,000
Discontinued operation, transaction costs					$ 10,500,000