Long-Term Debt (Long-Term Debt Interest Income) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Debt Instrument [Line Items]
Interest income	$ 2,837	$ 2,641	$ 8,470	$ 8,044

The amount of interest income and other income recognized during the period. Included in this element is interest derived from investments in debt securities, cash and cash equivalents, and other investments which reflect the time value of money or transactions in which the payments are for the use or forbearance of money and other income from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business).

No definition available.

Name:	us-gaap_InterestAndOtherIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration