Financing Agreements - Margin Based on Remaining Borrowing Availability (Detail)	9 Months Ended
	Sep. 30, 2014 LIBOR Rate [Member] Greater than $350 [Member] Revolving Facility [Member]	Sep. 30, 2014 LIBOR Rate [Member] Greater than $150 but less than or equal to $350 [Member] Revolving Facility [Member]	Sep. 30, 2014 LIBOR Rate [Member] $150 or less [Member] Revolving Facility [Member]	Sep. 30, 2014 Base Rate [Member] Greater than $350 [Member] Revolving Facility [Member]	Sep. 30, 2014 Base Rate [Member] Greater than $150 but less than or equal to $350 [Member] Revolving Facility [Member]	Sep. 30, 2014 Base Rate [Member] $150 or less [Member] Revolving Facility [Member]	Sep. 30, 2014 Senior Notes Due February 2019 [Member]	Dec. 31, 2013 Senior Notes Due February 2019 [Member]	Sep. 30, 2014 Senior Notes Due February 2021 [Member]	Dec. 31, 2013 Senior Notes Due February 2021 [Member]	Sep. 30, 2014 Senior Notes Due September 2021 [Member]	Dec. 31, 2013 Senior Notes Due September 2021 [Member]	Sep. 30, 2014 Senior Notes Due September 2023 [Member]	Dec. 31, 2013 Senior Notes Due September 2023 [Member]
Debt Instrument [Line Items]
Interest Rate							6.50%	6.50%	6.75%	6.75%	5.375%	5.375%	6.00%	6.00%
Margin rate	1.50%	1.75%	2.00%	0.50%	0.75%	1.00%