Noninterest Income and Expenses - Summary of Noninterest Income and Expense (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 17, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Noninterest income
Service charges on deposit accounts		$ 9,669	$ 8,563	$ 6,952
Trust fees		3,433	3,132	2,986
Mortgage banking fees		5,864	4,252	3,057
Brokerage commissions and fees		2,044	2,132	1,614
Marine finance fees		673	1,152	1,320
Interchange income		9,227	7,684	5,972
Other deposit based EFT fees		477	397	343
BOLI Income		2,213	1,426	252
Gain on participated loan		0	725	0
Other		3,827	2,555	2,248
Noninterest Income		37,427	32,018	24,744
Securities gains, net		368	161	469
Bargain purchase gain, net	$ (416)	0	416	0
TOTAL		37,795	32,595	25,213
Noninterest expense
Salaries and wages		54,096	41,075	35,132
Employee benefits		9,903	9,564	8,773
Outsourced data processing costs		13,516	10,150	8,781
Telephone / data lines		2,108	1,797	1,331
Occupancy		13,122	8,744	7,930
Furniture and equipment		4,720	3,434	2,535
Marketing		3,633	4,428	3,576
Legal and professional fees		9,596	8,022	6,871
FDIC assessments		2,365	2,212	1,660
Amortization of intangibles		2,486	1,424	1,033
Asset dispositions expense		553	472	488
Branch closures and new branding		0	0	4,958
Net (gain)/loss on other real estate owned and repossessed assets		(509)	239	310
Early redemption cost for Federal Home Loan Bank advances		1,777	0	0
Other		13,515	12,209	9,988
TOTAL		$ 130,881	$ 103,770	$ 93,366