Consolidated Statements of Changes In Shareholders' Equity (USD $) In Thousands, unless otherwise specified	Total		Class A Common Stock	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Surplus	Surplus Class B Common Stock	Retained Earnings	Retained Earnings Class B Common Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Class B Common Stock
Balance at Dec. 31, 2010	$ 1,732,962			$ 8,757	$ 1,678	$ 143,766		$ 1,615,290		$ (36,529)
Comprehensive income:
Net income	83,060			0	0	0		83,060		0
Other comprehensive income, net of tax	7,078			0	0	0		0		7,078
Total comprehensive income	90,138
Repurchase of Class B common stock shares	(7,575)		0		(38)		0		(7,537)		0
Cash dividends	(6,255)			0	0	0		(6,255)		0
Balance at Jun. 30, 2011	1,809,270	[1]		8,757	1,640	143,766		1,684,558		(29,451)
Balance at Dec. 31, 2011	1,861,128	[2]		8,644	1,640	143,766		1,773,652		(66,574)
Comprehensive income:
Net income	73,078			0	0	0		73,078		0
Other comprehensive income, net of tax	4,167			0	0	0		0		4,167
Total comprehensive income	77,245
Repurchase of Class B common stock shares	(2,414)		0		(13)		0		(2,401)		0
Cash dividends	(6,169)			0	0	0		(6,169)		0
Balance at Jun. 30, 2012	$ 1,929,790	[1]		$ 8,644	$ 1,627	$ 143,766		$ 1,838,160		$ (62,407)

[1] Unaudited

[2] Derived from 2011 Annual Report on Form 10-K.