Condensed Financial Information Of Parent Company Parent Company Information (Details 2) - 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	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net earnings	$ 71,841	$ 69,616	$ 85,083	$ 73,079	$ 70,999	$ 62,271	$ 10,555	$ 25,080	$ 299,619	$ 168,905	$ 45,115
Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract]
Decrease (increase) in other assets									48,172	49,498	19,789
Tax effect included in stockholders' equity of restricted stock vesting									(841)	(4,625)	(2,133)
Earned stock compensation									15,630	36,474	21,246
Net cash provided by operating activities									593,878	332,110	50,252
Net Cash Provided by (Used in) Investing Activities [Abstract]
Cash acquired in acquisitions, net of cash consideration paid									260,936	346,047	273,013
Payments to Acquire Available-for-sale Securities									(992,680)	(236,739)	(550,211)
Net Cash Provided by (Used in) Financing Activities [Abstract]
Tax effect included in stockholders' equity of restricted vesting stock									841	4,625	2,133
Restricted stock surrendered									8,400	22,307	13,537
Increase (Decrease) in Notes Receivables										0	0
Cash dividends paid, net									(215,110)	(114,162)	(41,006)
Net cash provided by (used in) financing activities									131,879	(722,864)	(480,173)
Cash and Cash Equivalents, at Carrying Value	396,486				313,226				396,486	313,226	147,422	$ 164,404
Supplemental Cash Flow Information [Abstract]
Common stock ($0.01 par value, 200,000,000 shares authorized at December 31, 2015 and 2014; 122,791,729 and 104,219,197 shares issued, respectively, includes 1,211,951 and 1,108,505 shares of unvested restricted stock, respectively)	1,228				1,042				1,228	1,042
Parent Only
Condensed Financial Statements, Captions [Line Items]
Net earnings									299,619	168,905	45,115
Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract]
Acquisition Related Securities Gain									0	0	(5,222)
Decrease (increase) in other assets									145,708	25,515	(609)
Increase (Decrease) in Operating Liabilities									9,115	310	4,932
Tax effect included in stockholders' equity of restricted stock vesting									841	4,625	(364)
Earned stock compensation									14,994	41,099	441
Income (Loss) from Equity Method Investments, Net of Dividends or Distributions									(91,198)	(38,935)	2,392
Net cash provided by operating activities									379,079	201,519	46,685
Net Cash Provided by (Used in) Investing Activities [Abstract]
Cash acquired in acquisitions, net of cash consideration paid									3,021	226,960	857
Net Cash Provided by (Used in) Investing Activities, Continuing Operations									3,021	226,960	857
Net Cash Provided by (Used in) Financing Activities [Abstract]
Tax effect included in stockholders' equity of restricted vesting stock									(841)	(4,625)	364
Restricted stock surrendered									(8,400)	(22,307)	(13,537)
Increase (Decrease) in Notes Receivables									(50,000)
Cash dividends paid, net									(215,110)	(114,162)	(41,006)
Net cash provided by (used in) financing activities									(274,351)	(141,094)	(54,179)
Net Cash Provided by (Used in) Continuing Operations									107,749	287,385	(6,637)
Cash and Cash Equivalents, at Carrying Value	416,969				309,220				416,969	309,220	21,835	$ 28,472
Supplemental Cash Flow Information [Abstract]
Common stock ($0.01 par value, 200,000,000 shares authorized at December 31, 2015 and 2014; 122,791,729 and 104,219,197 shares issued, respectively, includes 1,211,951 and 1,108,505 shares of unvested restricted stock, respectively)	$ 797,433				$ 2,594,070				$ 797,433	$ 2,594,070	$ 242,268