Loans (Summary of Recorded Investment of Commercial Loans by Risk Rating Categories) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	$ 12,715,789	$ 7,271,147
Commercial loan portfolio [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	7,433,447	4,250,117
Commercial loan portfolio [Member] | Commercial [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	3,159,936	1,905,879
Commercial loan portfolio [Member] | Commercial real estate [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	3,773,017	2,112,162
Commercial loan portfolio [Member] | Real estate construction and land development [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	500,494	232,076
Originated Portfolio [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	3,620,724	3,130,721
Originated Portfolio [Member] | Risk Grades 1-5 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	3,444,690	2,942,826
Originated Portfolio [Member] | Risk Grade 6 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	90,932	65,943
Originated Portfolio [Member] | Risk Grade 7 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	51,366	67,714
Originated Portfolio [Member] | Risk Grade 8 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	32,605	52,143
Originated Portfolio [Member] | Risk Grade 9 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	1,131	2,095
Originated Portfolio [Member] | Commercial [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	1,724,231	1,521,515
Originated Portfolio [Member] | Commercial [Member] | Risk Grades 1-5 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	1,624,836	1,418,301
Originated Portfolio [Member] | Commercial [Member] | Risk Grade 6 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	49,934	34,727
Originated Portfolio [Member] | Commercial [Member] | Risk Grade 7 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	35,719	39,933
Originated Portfolio [Member] | Commercial [Member] | Risk Grade 8 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	12,612	26,459
Originated Portfolio [Member] | Commercial [Member] | Risk Grade 9 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	1,130	2,095
Originated Portfolio [Member] | Commercial real estate [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	1,603,769	1,424,059
Originated Portfolio [Member] | Commercial real estate [Member] | Risk Grades 1-5 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	1,528,013	1,341,202
Originated Portfolio [Member] | Commercial real estate [Member] | Risk Grade 6 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	40,710	31,036
Originated Portfolio [Member] | Commercial real estate [Member] | Risk Grade 7 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	15,132	26,658
Originated Portfolio [Member] | Commercial real estate [Member] | Risk Grade 8 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	19,913	25,163
Originated Portfolio [Member] | Commercial real estate [Member] | Risk Grade 9 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	1	0
Originated Portfolio [Member] | Real estate construction and land development [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	292,724	185,147
Originated Portfolio [Member] | Real estate construction and land development [Member] | Risk Grades 1-5 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	291,841	183,323
Originated Portfolio [Member] | Real estate construction and land development [Member] | Risk Grade 6 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	288	180
Originated Portfolio [Member] | Real estate construction and land development [Member] | Risk Grade 7 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	515	1,123
Originated Portfolio [Member] | Real estate construction and land development [Member] | Risk Grade 8 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	80	521
Originated Portfolio [Member] | Real estate construction and land development [Member] | Risk Grade 9 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	0	0
Acquired Portfolio [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	3,812,723	1,119,396
Acquired Portfolio [Member] | Risk Grades 1-5 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	3,523,524	1,011,895
Acquired Portfolio [Member] | Risk Grade 6 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	145,250	54,803
Acquired Portfolio [Member] | Risk Grade 7 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	91,016	43,119
Acquired Portfolio [Member] | Risk Grade 8 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	52,933	9,579
Acquired Portfolio [Member] | Commercial [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	1,435,705	384,364
Acquired Portfolio [Member] | Commercial [Member] | Risk Grades 1-5 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	1,331,689	340,782
Acquired Portfolio [Member] | Commercial [Member] | Risk Grade 6 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	49,679	28,321
Acquired Portfolio [Member] | Commercial [Member] | Risk Grade 7 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	37,813	11,607
Acquired Portfolio [Member] | Commercial [Member] | Risk Grade 8 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	16,524	3,654
Acquired Portfolio [Member] | Commercial real estate [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	2,169,248	688,103
Acquired Portfolio [Member] | Commercial real estate [Member] | Risk Grades 1-5 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	1,988,676	629,430
Acquired Portfolio [Member] | Commercial real estate [Member] | Risk Grade 6 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	94,829	23,926
Acquired Portfolio [Member] | Commercial real estate [Member] | Risk Grade 7 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	52,317	29,975
Acquired Portfolio [Member] | Commercial real estate [Member] | Risk Grade 8 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	33,426	4,772
Acquired Portfolio [Member] | Real estate construction and land development [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	207,770	46,929
Acquired Portfolio [Member] | Real estate construction and land development [Member] | Risk Grades 1-5 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	203,159	41,683
Acquired Portfolio [Member] | Real estate construction and land development [Member] | Risk Grade 6 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	742	2,556
Acquired Portfolio [Member] | Real estate construction and land development [Member] | Risk Grade 7 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	886	1,537
Acquired Portfolio [Member] | Real estate construction and land development [Member] | Risk Grade 8 [Member]
Recorded investment of loans in commercial loan portfolio by risk rating categories
Total loans	$ 2,983	$ 1,153