Condensed Consolidated Statements of Stockholders' Equity (USD $) In Thousands	Total	COMMON STOCK:	CAPITAL SURPLUS:	ACCUMULATED OTHER COMPREHENSIVE INCOME:	RETAINED EARNINGS:
Balance at beginning of period at Dec. 31, 2012		$ 139	$ 798,093	$ 43,779
Balance at beginning of period, (in shares) at Dec. 31, 2012		139,439
Net issuances of restricted stock, (in shares)		510
Repurchases of common stock, (in shares)		(1,289)
Exercises of stock options, (in shares)		866
Net issuances of restricted stock		1	(1)
Net income	55,863				55,863
Foreign currency translation adjustments, net of tax	(5,771)			(5,771)
Repurchases of common stock		(1)			(45,672)
Cash dividends			(12,256)		(10,191)
Stock-based compensation expense			8,208
Exercise of stock options		1	19,938
Tax impact of equity incentive plans			2,394
Balance at end of period at Mar. 31, 2013		140	816,376	38,008
Balance at end of period, (in shares) at Mar. 31, 2013		139,526
Balance at beginning of period at Dec. 31, 2013	919,643	137	868,120	38,071	13,315
Balance at beginning of period, (in shares) at Dec. 31, 2013		137,466
Net issuances of restricted stock, (in shares)		747
Repurchases of common stock, (in shares)		(1,064)
Exercises of stock options, (in shares)		324
Net issuances of restricted stock		1	(1)
Net income	61,551				61,551
Foreign currency translation adjustments, net of tax	405			405
Repurchases of common stock		(1)			(43,290)
Cash dividends					(24,739)
Stock-based compensation expense			8,774
Exercise of stock options			8,676
Tax impact of equity incentive plans			1,127
Balance at end of period at Mar. 31, 2014	$ 932,146	$ 137	$ 886,696	$ 38,476	$ 6,837
Balance at end of period, (in shares) at Mar. 31, 2014		137,473