Consolidated Statements of Changes in Equity (Unaudited) (USD $) In Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total Shareholders' Equity [Member]	Non-Controlling Interests [Member]
Balance, beginning of period at Dec. 31, 2012	$ 2,993,681	$ 4	$ 859,278	$ 2,137,541	$ (188,883)	$ 149,920	$ 2,957,860	$ 35,821
Balance, beginning of period (in shares) at Dec. 31, 2012		72,415			4,088
Net income	89,059			87,964			87,964	1,095
Other comprehensive income (loss)	(16,537)					(16,537)	(16,537)
Issuance of shares for equity compensation (in shares)		531			170
Issuance of shares for equity compensation	9,542		18,178		(8,636)		9,542
Tax effect from equity compensation, net	(337)		(337)				(337)
Stock-based compensation	(751)		(751)				(751)
Cash dividends on common stock	(25,783)			(25,783)			(25,783)
Capital calls and distributions, net	(982)							(982)
Balance, end of period at Mar. 31, 2013	3,047,892	4	876,368	2,199,722	(197,519)	133,383	3,011,958	35,934
Balance, end of period (in shares) at Mar. 31, 2013		72,946			4,258
Balance, beginning of period at Dec. 31, 2013	3,054,973	4	898,586	2,349,428	(202,346)	(25,623)	3,020,049	34,924
Balance, beginning of period (in shares) at Dec. 31, 2013		73,163			4,305
Net income	77,043			76,590			76,590	453
Other comprehensive income (loss)	32,418					32,418	32,418
Issuance of shares for equity compensation (in shares)		385			103
Issuance of shares for equity compensation	3,655		10,461		(6,806)		3,655
Tax effect from equity compensation, net	1,732		1,732				1,732
Stock-based compensation	2,863		2,863				2,863
Cash dividends on common stock	(27,382)			(27,382)			(27,382)
Capital calls and distributions, net	(703)							(703)
Balance, end of period at Mar. 31, 2014	$ 3,144,599	$ 4	$ 913,642	$ 2,398,636	$ (209,152)	$ 6,795	$ 3,109,925	$ 34,674
Balance, end of period (in shares) at Mar. 31, 2014		73,548			4,408