Debt Outstanding Matures on Calendar Year Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Debt Disclosure [Line Items]
Contractual debt obligation maturities 2012	$ 4,862
Contractual debt obligation maturities 2013	201,788
Contractual debt obligation maturities 2014	1,168
Contractual debt obligation maturities 2015	1,168
Contractual debt obligation maturities 2016	290,153
Contractual debt obligation maturities Thereafter	809,948
Total	1,309,087	707,472
Contractual Maturity
Debt Disclosure [Line Items]
Contractual debt obligation maturities 2012	3,694
Contractual debt obligation maturities 2013	200,620
Contractual debt obligation maturities 2016	288,985
Contractual debt obligation maturities Thereafter	800,000
Total	1,293,299
Capital Lease Obligations
Debt Disclosure [Line Items]
Contractual debt obligation maturities 2012	1,168
Contractual debt obligation maturities 2013	1,168
Contractual debt obligation maturities 2014	1,168
Contractual debt obligation maturities 2015	1,168
Contractual debt obligation maturities 2016	1,168
Contractual debt obligation maturities Thereafter	9,948
Total	$ 15,788