Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands		Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2016			13,750	44,795,386
Beginning balance at Dec. 31, 2016		$ 2,939,694	$ 132,097	$ 44,795	$ 2,084,446	$ 704,391	$ (26,035)
Increase (Decrease) in Shareholders' Equity
Net income		142,413				142,413
Other comprehensive income (loss)		(11,721)					(11,721)
Cash dividends declared		(76,615)				(76,615)
Reclassification of AOCI to RE due to Tax Act	[1]	8,132					(8,132)
Preferred stock dividends		(9,095)				(9,095)
Common stock issued under incentive plans, net of shares surrendered in payment (in shares)				366,582
Common stock issued under incentive plans, net of shares surrendered in payment		(515)		$ 367	(882)
Stock issued (in shares)				6,100,000
Stock issued		485,151		$ 6,100	479,051
Common stock issued for acquisitions (in shares)				2,610,304
Common stock issued for acquisitions		211,043		$ 2,610	208,433
Share-based compensation expense		16,436			16,436
Ending balance (in shares) at Dec. 31, 2017			13,750	53,872,272
Ending balance at Dec. 31, 2017		3,696,791	$ 132,097	$ 53,872	2,787,484	769,226	(45,888)
Increase (Decrease) in Shareholders' Equity
Net income		370,249				370,249
Other comprehensive income (loss)		3,138					3,138
Cash dividends declared		(87,317)				(87,317)
Preferred stock dividends		(9,095)				(9,095)
Common stock issued under incentive plans, net of shares surrendered in payment (in shares)				108,686
Common stock issued under incentive plans, net of shares surrendered in payment		(3,226)		$ 109	(3,335)
Common stock issued for acquisitions (in shares)				2,787,773
Common stock issued for acquisitions		214,659		$ 2,788	211,871
Share-based compensation expense		20,278			20,278
Common stock repurchases (in shares)				(1,972,500)
Common stock repurchases		(148,855)		$ (1,973)	(146,882)
Ending balance (in shares) at Dec. 31, 2018			13,750	54,796,231
Ending balance at Dec. 31, 2018		4,056,277	$ 132,097	$ 54,796	2,869,416	1,042,718	(42,750)
Increase (Decrease) in Shareholders' Equity
Net income		384,155				384,155
Other comprehensive income (loss)		87,511					87,511
Cash dividends declared		(93,313)				(93,313)
Preferred stock dividends		(12,602)				(12,602)
Common stock issued under incentive plans, net of shares surrendered in payment (in shares)				323,288
Common stock issued under incentive plans, net of shares surrendered in payment		(3,373)		$ 324	(3,697)
Stock issued (in shares)			10,000
Stock issued		96,388	$ 96,388
Share-based compensation expense		24,584			24,584
Common stock repurchases (in shares)				(2,700,000)
Common stock repurchases		(204,740)		$ (2,700)	(202,040)
Ending balance (in shares) at Dec. 31, 2019			23,750	52,419,519
Ending balance at Dec. 31, 2019		$ 4,336,734	$ 228,485	$ 52,420	$ 2,688,263	$ 1,322,805	$ 44,761

[1] (1) One-time reclassification from accumulated other comprehensive income ("AOCI") to retained earnings ("RE") for stranded tax effects resulting from the Tax Cuts and Jobs Act (the "Tax Act"), enacted on December 22, 2017.