Indebtedness - Debt Outstanding (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Bank debt percentage	1.90%	1.90%
8.00% Senior Subordinated notes due 2019
Debt Instrument [Line Items]
Interest rate on senior subordinated notes	8.00%	8.00%
Discount on Senior Subordinated notes	$ 9,134	$ 9,484
6.75% Senior Subordinated notes due 2020
Debt Instrument [Line Items]
Interest rate on senior subordinated notes	6.75%	6.75%
5.75% Senior Subordinated notes due 2021
Debt Instrument [Line Items]
Interest rate on senior subordinated notes	5.75%	5.75%
5.00% Senior Subordinated notes due 2022
Debt Instrument [Line Items]
Interest rate on senior subordinated notes	5.00%	5.00%
5.00% Senior Subordinated notes due 2023
Debt Instrument [Line Items]
Interest rate on senior subordinated notes		5.00%