Revision of 2011 and 2012 Financial Statements - Effect of Revisions on Affected Line Items on Consolidated Balance Sheet (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Feb. 28, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Balance Sheet Data:
Cash and cash equivalents	$ 215,771		$ 243,465	$ 223,849	$ 157,704
Restricted cash	5,636		3,478
Accounts receivable, net	99,530		78,928
Deferred income taxes (current)	77,549		44,547
Total current assets	434,616		386,580
Deferred income taxes	68,324		57,471
Total assets	806,851	6,614	675,204
Other current liabilities	42,136	3,060	106,796
Total current liabilities	473,777		327,023
Other liabilities	146,087	43,054	82,416
Total	691,205	46,114	549,439
Capital surplus	200,040		197,113
Retained earnings	940,449		967,473
Total shareholders' equity	115,646		125,765	169,105	127,042
Total liabilities and shareholders' equity	806,851		675,204
As Previously Reported [Member]
Balance Sheet Data:
Cash and cash equivalents			246,342
Restricted cash			601
Accounts receivable, net			77,313
Deferred income taxes (current)			44,547
Total current assets			384,965
Deferred income taxes			56,112
Total assets			672,230
Other current liabilities			86,722
Total current liabilities			306,949
Other liabilities			98,327
Total			545,276
Capital surplus			206,703
Retained earnings			959,072
Total shareholders' equity			126,954
Total liabilities and shareholders' equity			672,230
Revisions [Member]
Balance Sheet Data:
Cash and cash equivalents			(2,877)
Restricted cash			2,877
Accounts receivable, net			1,615
Deferred income taxes (current)			0
Total current assets			1,615
Deferred income taxes			1,359
Total assets			2,974
Other current liabilities			20,074
Total current liabilities			20,074
Other liabilities			(15,911)
Total			4,163
Capital surplus			(9,590)
Retained earnings			8,401
Total shareholders' equity			(1,189)
Total liabilities and shareholders' equity			$ 2,974