Debt - Summary of Components of Debt (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Total debt	$ 3,625,115	$ 1,146,249
Term Loan [Member]
Debt Instrument [Line Items]
Total debt	1,660,993	679,598
4.5% Convertible Senior Subordinated Notes Due 2019 [Member]
Debt Instrument [Line Items]
Total debt	211,385	207,135
Master Repurchase Agreements [Member]
Debt Instrument [Line Items]
Total debt	1,749,561	255,385
Other [Member]
Debt Instrument [Line Items]
Total debt	$ 3,176	$ 4,131