Consolidating Statement of Cash Flows (Parenthetical) (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Condensed Cash Flow Statements Captions [Line Items]
Debt instrument interest rate	6.75%		6.75%
6.75% Unsecured Notes Due 2019
Condensed Cash Flow Statements Captions [Line Items]
Debt instrument interest rate	6.75%	6.75%	6.75%	6.75%	6.75%
Debt instrument maturity date	Mar. 01, 2019	Mar. 01, 2019	Mar. 01, 2019	Mar. 01, 2019	Mar. 01, 2019