Other Assets- Additional Information (Detail) (USD $)	3 Months Ended					6 Months Ended
	Jun. 30, 2014		Mar. 31, 2014	Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013	Dec. 31, 2013
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, before Tax	$ 0	[1]	$ 7,700,000	$ 0	[1]	$ 7,718,000		$ 0
Securities Trades Receivables	519,495,000	[2]		158,141,000		519,495,000	[2]	158,141,000	71,680,000
Fixed Rate 700 Percent Notes Due July 2019 [Member]
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Senior Long Term Notes	450,000,000					450,000,000			0
Debt Issuance Costs	9,000,000
Securities Trades Receivables	441,000,000					441,000,000
Centro Financiero BHD [Member]
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Line Items]
Equity Method Investment Ownership Percentage	15.82%		15.79%			15.82%			19.99%
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Reclassification Adjustment Realized upon Sale or Liquidation, before Tax			7,700,000
Share Of Changes In Stockholders Equity			$ 14,200,000

[1] All amounts presented are net of tax.

[2] Includes $441 million of trades receivable as of June 30,2014, related to the issuance of $450 million in Senior Notes, which settled on July 1, 2014, net of debt issuance costs of $9 million.