Consolidated Statements of Changes in Equity (Unaudited) (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total shareholders' Equity [Member]	Non-Controlling Interest [Member]
Balances at Dec. 31, 2009	$ 2,225,374	$ 4	$ (10,740)	$ 758,723	$ 1,563,683	$ (105,857)	$ 2,205,813	$ 19,561
Balances (in shares) at Dec. 31, 2009		70,312,000				2,509,000
Net income	248,294				246,754		246,754	1,540
Other comprehensive income	118,579		118,579				118,579	0
Exercise of stock options (in shares)		504,000				99,000
Exercise of stock options	8,552			15,497		(6,945)	8,552
Tax benefit on exercise of stock options	425			425			425
Stock-based compensation	8,160			8,160			8,160
Cash dividends on common stock	(66,557)				(66,557)		(66,557)
Capital calls and distributions, net	1,051							1,051
Balances at Dec. 31, 2010	2,543,878	4	107,839	782,805	1,743,880	(112,802)	2,521,726	22,152
Balances (in shares) at Dec. 31, 2010		70,816,000				2,608,000
Net income	289,824				285,875		285,875	3,949
Other comprehensive income	21,140		21,140				21,140	0
Treasury stock purchases (in shares)						562,000
Treasury stock purchases	(26,446)					(26,446)	(26,446)
Exercise of stock options (in shares)		717,000				210,000
Exercise of stock options	14,541			25,957		(11,416)	14,541
Tax benefit on exercise of stock options	659			659			659
Stock-based compensation	9,396			9,396			9,396
Cash dividends on common stock	(76,423)				(76,423)		(76,423)
Capital calls and distributions, net	10,083							10,083
Balances at Dec. 31, 2011	2,786,652	4	128,979	818,817	1,953,332	(150,664)	2,750,468	36,184
Balances (in shares) at Dec. 31, 2011		71,533,000				3,380,000
Net income	354,124				351,191		351,191	2,933
Other comprehensive income	20,941		20,941				20,941	0
Treasury stock purchases (in shares)						384,000
Treasury stock purchases	(20,558)					(20,558)	(20,558)
Exercise of stock options (in shares)		882,000				324,000
Exercise of stock options	14,650			32,311		(17,661)	14,650
Tax benefit on exercise of stock options	120			120			120
Stock-based compensation	8,030			8,030			8,030
Cash dividends on common stock	(166,982)				(166,982)		(166,982)
Acquisition of non-controlling interest	1,645							1,645
Capital calls and distributions, net	4,941							(4,941)
Balances at Dec. 31, 2012	$ 2,993,681	$ 4	$ 149,920	$ 859,278	$ 2,137,541	$ (188,883)	$ 2,957,860	$ 35,821
Balances (in shares) at Dec. 31, 2012		72,415,000				4,088,000