Loans (Summary of Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Summary of loans under portfolio
Total loans	$ 12,715,789	$ 7,271,147
Commercial loan portfolio [Member]
Summary of loans under portfolio
Total loans	7,433,447	4,250,117
Commercial loan portfolio [Member] | Commercial [Member]
Summary of loans under portfolio
Total loans	3,159,936	1,905,879
Commercial loan portfolio [Member] | Commercial real estate [Member]
Summary of loans under portfolio
Total loans	3,773,017	2,112,162
Commercial loan portfolio [Member] | Real estate construction and land development [Member]
Summary of loans under portfolio
Total loans	500,494	232,076
Consumer loan portfolio [Member]
Summary of loans under portfolio
Total loans	5,282,342	3,021,030
Consumer loan portfolio [Member] | Residential mortgage [Member]
Summary of loans under portfolio
Total loans	3,046,959	1,429,636
Consumer loan portfolio [Member] | Consumer installment [Member]
Summary of loans under portfolio
Total loans	1,335,707	877,457
Consumer loan portfolio [Member] | Home equity [Member]
Summary of loans under portfolio
Total loans	$ 899,676	$ 713,937