Condensed Parent Company Financial Statements (Statements Of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Activities:
Net income	$ 35,512	$ 38,355	$ 43,831	$ 39,052	$ 38,133	$ 40,224	$ 38,541	$ 34,500	$ 156,749	$ 151,398	$ 137,210
Adjustments to reconcile net income to net cash provided by (used for) operating activities
Provision for credit losses	9,059	8,322	9,482	6,079	6,133	5,864	6,660	1,880	32,942	20,537	46,033
Losses (gains) on available-for-sale securities, net	79	$ 98	$ 24	(524)	(18)	$ 153	$ 336	33	(323)	504	3,000
Depreciation and amortization									36,671	32,117	26,180
Deferred income tax expense									23,054	4,125	1,539
Stock-based compensation expense									9,656	7,754	6,799
Excess tax benefits from stock-based compensation arrangements									(744)	(444)	(474)
Increase in other assets									(147,063)	77,409	53,166
Increase in other liabilities									292	(38,902)	(21,749)
Net Cash (Used for) Provided by Operating Activities									37,952	205,623	287,209
Investing Activities:
Net cash paid for acquisitions, net									(15,428)	228,946	(14,491)
Net Cash Used for Investing Activities									(1,641,553)	(1,837,592)	(206,221)
Financing Activities:
Decrease in other borrowings, net									44,685	(58,639)	(22,396)
Proceeds from issuance of subordinated notes, net									0	139,090	0
Repayment of subordinated note									0	0	(15,000)
Excess tax benefits from stock-based compensation arrangements									744	444	474
Net proceeds from issuance of Series D preferred stock									120,842	0	0
Issuance of common shares resulting from exercise of stock options, employee stock purchase plan and conversion of common stock warrants									16,119	10,453	19,113
Dividends paid									(29,888)	(24,933)	(13,893)
Common stock repurchases									(424)	(549)	(3,504)
Net Cash Provided by (Used for) Financing Activities									1,648,689	1,598,812	(132,152)
Net (Decrease) Increase in Cash and Cash Equivalents									45,088	(33,157)	(51,164)
Cash and Cash Equivalents at Beginning of Period				230,707				263,864	230,707	263,864	315,028
Cash and Cash Equivalents at End of Period	275,795				230,707				275,795	230,707	263,864
Reportable Legal Entities [Member] | Parent Company [Member]
Operating Activities:
Net income									156,749	151,398	137,210
Adjustments to reconcile net income to net cash provided by (used for) operating activities
Provision for credit losses									(96)	945	1,765
Losses (gains) on available-for-sale securities, net									0	33	(111)
Depreciation and amortization									8,182	7,756	3,744
Deferred income tax expense									(1,872)	2,753	1,217
Stock-based compensation expense									9,656	7,754	6,799
Excess tax benefits from stock-based compensation arrangements									(278)	(139)	(112)
Increase in other assets									(45,287)	(10,090)	(3,882)
Increase in other liabilities									21,840	7,114	(4,517)
Equity in undistributed net income of subsidiaries									(183,830)	(111,622)	(55,724)
Net Cash (Used for) Provided by Operating Activities									(34,936)	55,902	86,389
Investing Activities:
Capital contributions to subsidiaries, net									(97,400)	(105,244)	(8,293)
Net cash paid for acquisitions, net									(51,060)	0	0
Other investing activity, net									(24,908)	(3,907)	(21,206)
Net Cash Used for Investing Activities									(173,368)	(109,151)	(29,499)
Financing Activities:
Decrease in other borrowings, net									66,963	(517)	(17,860)
Proceeds from issuance of subordinated notes, net									0	139,090	0
Repayment of subordinated note									0	0	(15,000)
Excess tax benefits from stock-based compensation arrangements									278	139	112
Net proceeds from issuance of Series D preferred stock									120,842	0	0
Issuance of common shares resulting from exercise of stock options, employee stock purchase plan and conversion of common stock warrants									16,119	10,453	19,113
Dividends paid									(29,888)	(24,933)	(13,893)
Common stock repurchases									(424)	(549)	(3,504)
Net Cash Provided by (Used for) Financing Activities									173,890	123,683	(31,032)
Net (Decrease) Increase in Cash and Cash Equivalents									(34,414)	70,434	25,858
Cash and Cash Equivalents at Beginning of Period				$ 151,303				$ 80,869	151,303	80,869	55,011
Cash and Cash Equivalents at End of Period	$ 116,889				$ 151,303				$ 116,889	$ 151,303	$ 80,869