Parent Company Condensed Financial Statements (Condensed Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
ASSETS
Cash and cash equivalents due from subsidiary bank	$ 3,261,149	$ 3,001,377
Goodwill	465,697	465,547	$ 469,433
Other assets	917,095	743,686
TOTAL	44,196,096	41,042,356	37,121,563
LIABILITIES
Long-term debt		146,835
Total liabilities	39,178,479	36,618,382
STOCKHOLDERS’ EQUITY
Common stock, $0.001 par value, 200,000,000 shares authorized; 166,621,959 and 165,867,587 shares issued in 2019 and 2018, respectively	167	166
Additional paid-in capital	1,826,345	1,789,811
Retained earnings	3,689,377	3,160,132
Treasury stock, at cost — 20,996,574 shares in 2019 and 20,906,224 shares in 2018	(479,864)	(467,961)
AOCI, net of tax	(18,408)	(58,174)
Total stockholders’ equity	5,017,617	4,423,974	$ 3,841,951	$ 3,427,741
TOTAL	44,196,096	41,042,356
Parent Company
ASSETS
Cash and cash equivalents due from subsidiary bank	166,131	149,411
Investments in tax credit and other investments, net	11,637	23,259
Goodwill	150	0
Other assets	3,941	6,487
TOTAL	5,175,155	4,584,679
LIABILITIES
Long-term debt	147,101	146,835
Other liabilities	10,437	13,870
Total liabilities	157,538	160,705
STOCKHOLDERS’ EQUITY
Common stock, $0.001 par value, 200,000,000 shares authorized; 166,621,959 and 165,867,587 shares issued in 2019 and 2018, respectively	167	166
Additional paid-in capital	1,826,345	1,789,811
Retained earnings	3,689,377	3,160,132
Treasury stock, at cost — 20,996,574 shares in 2019 and 20,906,224 shares in 2018	(479,864)	(467,961)
AOCI, net of tax	(18,408)	(58,174)
Total stockholders’ equity	5,017,617	4,423,974
TOTAL	5,175,155	4,584,679
Parent Company | Bank
Balance sheets
Investments in Subsidiaries	4,987,666	4,401,860
Parent Company | Nonbank
Balance sheets
Investments in Subsidiaries	$ 5,630	$ 3,662