Loans - Summary of Acquired non-credit impaired loans (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Summary of Loans
Total loans		$ 11,375,104	$ 11,146,122
Unamortized Discounts	$ 52,200
Construction and land development
Summary of Loans
Total loans		1,017,261	946,503
Consumer Owner Occupied Loans
Summary of Loans
Total loans		2,706,960	2,731,499
Other income producing property
Summary of Loans
Total loans		346,554	380,177
Commercial loans | Commercial non-owner occupied
Summary of Loans
Total loans		2,323,967	2,329,449
Commercial loans | Commercial non-owner occupied real estate
Summary of Loans
Total loans		3,341,228	3,275,952
Commercial loans | Commercial owner occupied real estate loan
Summary of Loans
Total loans		2,158,701	2,086,662
Commercial loans | Commercial and industrial
Summary of Loans
Total loans		1,386,327	1,251,719
Commercial loans | Other loans
Summary of Loans
Total loans		13,892	18,224
Consumer | Home equity loans
Summary of Loans
Total loans		758,020	791,658
Consumer | Real estate
Summary of Loans
Total loans		3,464,980	3,523,157
Consumer | Consumer
Summary of Loans
Total loans		663,422	610,231
Acquired non-credit impaired loans
Summary of Loans
Total loans		1,760,427	2,378,737
Unamortized Discounts		20,300	30,200
Acquired non-credit impaired loans | Other income producing property
Summary of Loans
Total loans		95,697	120,696
Acquired non-credit impaired loans | Commercial loans
Summary of Loans
Total loans		985,780	1,438,160
Acquired non-credit impaired loans | Commercial loans | Construction and land development
Summary of Loans
Total loans		33,569	113,572
Acquired non-credit impaired loans | Commercial loans | Commercial non-owner occupied
Summary of Loans
Total loans		447,441	629,394
Acquired non-credit impaired loans | Commercial loans | Commercial non-owner occupied real estate
Summary of Loans
Total loans		481,010	742,966
Acquired non-credit impaired loans | Commercial loans | Commercial owner occupied real estate loan
Summary of Loans
Total loans		307,193	400,658
Acquired non-credit impaired loans | Commercial loans | Commercial and industrial
Summary of Loans
Total loans		101,880	173,840
Acquired non-credit impaired loans | Commercial loans | Other income producing property
Summary of Loans
Total loans		95,697	120,696
Acquired non-credit impaired loans | Consumer
Summary of Loans
Total loans		774,647	940,577
Acquired non-credit impaired loans | Consumer | Consumer Owner Occupied Loans
Summary of Loans
Total loans		496,431	610,376
Acquired non-credit impaired loans | Consumer | Home equity loans
Summary of Loans
Total loans		188,732	225,278
Acquired non-credit impaired loans | Consumer | Real estate
Summary of Loans
Total loans		685,163	835,654
Acquired non-credit impaired loans | Consumer | Consumer
Summary of Loans
Total loans		$ 89,484	$ 104,923