Parent Company Only Condensed Financial Statements (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows From Operating Activities
Net income	$ 232,516	$ 209,133	$ 176,055
Adjustments to net income:
Other, net	31,505	(28,632)	(11,459)
Net cash provided by operating activities	420,584	262,353	608,021
Cash Flows From Investing Activities
Purchase of securities available-for-sale	(3,371,639)	(5,362,435)	(5,288,118)
Other, net	71,747	97,765	122,649
Net cash used in investing activities	(775,069)	(4,390,121)	(2,715,318)
Cash Flows From Financing Activities
Proceeds from exercise of stock options	40,466	22,428	5,089
Issuance of preferred stock	97,696	169,920
Cash dividends	(50,375)	(80,380)	(42,489)
Other, net	(2,253)	(3,270)	(28,818)
Net cash provided by financing activities	875,026	4,298,359	1,917,422
Net increase (decrease) in cash and cash equivalents	520,541	170,591	(189,875)
Cash and cash equivalents at beginning of year	415,405	244,814	434,689
Cash and cash equivalents at end of period	935,946	415,405	244,814
Parent Company
Cash Flows From Operating Activities
Net income	230,009	208,049	172,421
Adjustments to net income:
Equity in undistributed income of Bank and non-bank subsidiaries	(184,119)	(123,797)	(141,358)
Other, net	13,287	13,199	20,382
Net cash provided by operating activities	59,177	97,451	51,445
Cash Flows From Investing Activities
Purchase of securities available-for-sale	(29,942)		(65,019)
Sales and paydowns of securities available-for-sale	33,806	16,516	77,779
Net advances to subsidiaries	(100,000)	(1,335)
Other, net	2,275	11,641	11,036
Net cash used in investing activities	(93,861)	26,822	23,796
Cash Flows From Financing Activities
Net decrease in other borrowings	(205,535)	(1,875)	(757)
Proceeds from exercise of stock options	40,466	22,428	5,089
Issuance of preferred stock	97,536	169,108
Cash dividends	(50,375)	(80,380)	(42,489)
Other, net	4,717	3,089	1,999
Net cash provided by financing activities	(113,191)	112,370	(36,158)
Net increase (decrease) in cash and cash equivalents	(147,875)	236,643	39,083
Cash and cash equivalents at beginning of year	295,314	58,671	19,588
Cash and cash equivalents at end of period	$ 147,439	$ 295,314	$ 58,671