Components Of Deferred Tax Assets And Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred Income Tax Assets And Liabilities [Line Items]
Asset reserves and liabilities not yet deductible for tax	$ 12,198	$ 14,350
Net current deferred tax assets	12,198	14,350
Current deferred tax liabilities, Other	(4,176)	(2,582)
Net total current deferred tax assets	8,022	11,768
Asset reserves and liabilities not yet deductible for tax	24,392	21,145
Tax over book basis of certain assets	13,994	17,347
Net operating loss and tax credit carryforwards	8,843	9,095
Noncurrent deferred tax assets, Other	261	874
Total noncurrent deferred tax assets	47,490	48,461
Less valuation allowance	(2,655)	(2,862)
Net noncurrent deferred tax assets	44,835	45,599
Book over tax basis of certain assets	(184,334)	(182,084)
Deferred tax liabilities, other	(27)	(18)
Total noncurrent deferred tax liabilities	(184,361)	(182,102)
Net total noncurrent deferred tax liabilities	$ (139,526)	$ (136,503)