Parent Company Only Condensed Financial Statements (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash Flows From Operating Activities
Net income	$ 209,133	$ 176,055	$ 135,097
Adjustments to net income:
Other, net	(28,632)	(11,459)	(40,379)
Net cash provided by operating activities	262,353	608,021	580,009
Cash Flows From Investing Activities
Purchase of securities available-for-sale	(5,362,435)	(5,288,118)	(4,351,981)
Cash paid for acquisition	(123,746)	28,066	88,795
Other, net	97,765	122,649	82,196
Net cash used in investing activities	(4,390,121)	(2,715,318)	(383,930)
Cash Flows From Financing Activities
Cash dividends	(80,380)	(42,489)	(24,012)
Issuance (redemption) of preferred stock	(169,920)		200,000
Repurchase of common stock warrants			(18,500)
Proceeds from exercise of stock options	22,428	5,089	23,764
Other, net	(3,270)	(28,818)	(5,450)
Net cash provided by (used in) financing activities	4,298,359	1,917,422	(574,316)
Net increase (decrease) in cash and cash equivalents	170,591	(189,875)	(378,237)
Cash and cash equivalents at beginning of year	244,814	434,689	812,926
Cash and cash equivalents at end of period	415,405	244,814	434,689
Parent Company
Cash Flows From Operating Activities
Net income	208,049	172,421	130,464
Adjustments to net income:
Equity in undistributed income of Bank and non-bank subsidiaries	(123,797)	(141,358)	(139,486)
Other, net	13,199	20,382	13,127
Net cash provided by operating activities	97,451	51,445	4,105
Cash Flows From Investing Activities
Purchase of securities available-for-sale		(65,019)	(352,133)
Sales and paydowns of securities available-for-sale	16,516	77,779	304,694
Net advances to subsidiaries	(1,335)		(8,265)
Cash paid for acquisition			(6,140)
Other, net	11,641	11,036	2,520
Net cash used in investing activities	26,822	23,796	(59,324)
Cash Flows From Financing Activities
Net (decrease) increase in other borrowings	(1,875)	(757)	50,000
Cash dividends	(80,380)	(42,489)	(24,012)
Issuance (redemption) of preferred stock	169,108		(200,000)
Repurchase of common stock warrants			(18,500)
Proceeds from exercise of stock options	22,428	5,089	23,764
Other, net	3,089	1,999	470
Net cash provided by (used in) financing activities	112,370	(36,158)	(168,278)
Net increase (decrease) in cash and cash equivalents	236,643	39,083	(223,497)
Cash and cash equivalents at beginning of year	58,671	19,588	243,085
Cash and cash equivalents at end of period	$ 295,314	$ 58,671	$ 19,588