Debt Facilities - Summary of Senior Notes (Parenthetical) (Detail)	6 Months Ended
	Jun. 30, 2014
5.375% Senior Notes due 2023 [Member]
Debt Instrument [Line Items]
Senior notes stated percentage	5.375%
Senior notes maturity	2023
7.00% Senior Notes due 2021 [Member]
Debt Instrument [Line Items]
Senior notes stated percentage	7.00%
Senior notes maturity	2021
4.875% Senior Notes due 2020 [Member]
Debt Instrument [Line Items]
Senior notes stated percentage	4.875%
Senior notes maturity	2020