Loans and Allowance for Loan Losses - Activity in the Allowance for Loan Losses, by Portfolio Segment, for the Current Year (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	$ 42,086	$ 37,240
Provision for loan losses	38,148	26,393	$ 20,065
Balance, end of period	56,694	42,086	37,240
Loans, Excluding Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	41,668	36,286	31,351
Provision for loan losses	34,849	24,527	19,439
Charge-offs	(23,216)	(23,498)	(16,643)
Recoveries	3,298	4,353	2,139
Net charge-offs	(19,918)	(19,145)	(14,504)
Balance, end of period	56,599	41,668	36,286
Loans individually evaluated for impairment	684	338
Loans collectively evaluated for impairment	55,915	41,330
Loans acquired
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	418	954
Provision for loan losses	3,299	1,866	626
Charge-offs	(3,622)	(2,400)
Balance, end of period	95	418	954
Other Consumer and Other | Loans, Excluding Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	3,596	2,951	1,951
Provision for loan losses	4,903	2,173	2,459
Charge-offs	(6,637)	(3,767)	(1,975)
Recoveries	557	2,239	516
Net charge-offs	(6,080)	(1,528)	(1,459)
Balance, end of period	2,419	3,596	2,951
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	2,419	3,596
Commercial | Loans, Excluding Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	7,007	7,739	5,985
Provision for loan losses	19,385	7,002	5,345
Charge-offs	(6,623)	(7,837)	(3,956)
Recoveries	745	103	365
Net charge-offs	(5,878)	(7,734)	(3,591)
Balance, end of period	20,514	7,007	7,739
Loans individually evaluated for impairment	437	0
Loans collectively evaluated for impairment	20,077	7,007
Real Estate | Loans, Excluding Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	27,281	21,817	19,522
Provision for loan losses	7,376	12,463	9,461
Charge-offs	(5,905)	(7,989)	(7,517)
Recoveries	991	990	351
Net charge-offs	(4,914)	(6,999)	(7,166)
Balance, end of period	29,743	27,281	21,817
Loans individually evaluated for impairment	247	338
Loans collectively evaluated for impairment	29,496	26,943
Consumer | Loans, Excluding Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Net charge-offs	(9,126)	(4,412)
Consumer | Credit Card | Loans, Excluding Acquired Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of period	3,784	3,779	3,893
Provision for loan losses	3,185	2,889	2,174
Charge-offs	(4,051)	(3,905)	(3,195)
Recoveries	1,005	1,021	907
Net charge-offs	(3,046)	(2,884)	(2,288)
Balance, end of period	3,923	3,784	$ 3,779
Loans individually evaluated for impairment	0	0
Loans collectively evaluated for impairment	$ 3,923	$ 3,784