Significant Components of Non-Current Deferred Tax Liabilities and Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Deferred Tax Assets Liabilities [Line Items]
Fixed assets	$ 12,427	$ 11,400
Net unrealized holding gain of available-for-sale securities		4
Prepaid insurance and pension		3,123
Intangible assets	245,020	176,459
Total non-current deferred tax liabilities	257,447	190,986
Deferred compensation	13,576	11,341
Net operating loss carryforwards	6,658	2,071
Valuation allowance for deferred tax assets	(417)	(478)
Total non-current deferred tax assets	19,817	12,934
Net non-current deferred tax liability	$ 237,630	$ 178,052