Consolidated Statements Of Changes In Equity (USD $) In Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Non-Controlling Interest [Member]
Balance at Dec. 31, 2011	$ 2,170,361	$ 446,387	$ 1,042,065	$ 575,419	$ (8,362)	$ 110,538	$ 4,314
Net income	66,814			65,799			1,015
Other comprehensive income	7,518					7,518
Distributions to non-controlling interest	(1,459)						(1,459)
Purchase of treasury stock	(31,600)				(31,600)
Issuance of stock under purchase and equity compensation plans	5,954		(3,065)		9,019
Net tax benefit related to equity compensation plans	649		649
Stock-based compensation	1,407		1,407
Issuance of nonvested stock awards	0		(8,071)		8,071
Cash dividends	(20,438)			(20,438)
Balance at Mar. 31, 2012	2,199,206	446,387	1,032,985	620,780	(22,872)	118,056	3,870
Balance at Dec. 31, 2012	2,171,574	458,646	1,102,507	477,210	(7,580)	136,344	4,447
Net income	60,808			61,017			(209)
Other comprehensive income	(6,581)					(6,581)
Distributions to non-controlling interest	(192)						(192)
Purchase of treasury stock	(29,993)				(29,993)
Issuance of stock under purchase and equity compensation plans	2,606		(1,146)		3,752
Net tax benefit related to equity compensation plans	181		181
Stock-based compensation	1,223		1,223
Issuance of nonvested stock awards	0		(1,320)		1,320
Cash dividends	(20,435)			(20,435)
Balance at Mar. 31, 2013	$ 2,179,191	$ 458,646	$ 1,101,445	$ 517,792	$ (32,501)	$ 129,763	$ 4,046