Disclosures about Fair Value of Assets and Liabilities - Carrying Value and Estimated Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financial assets:
Loans held for sale	$ 51,768
Carrying Value
Financial assets:
Cash and cash equivalents	352,403	$ 359,519
Securities purchased under agreements to resell	6,954	7,043
FHLB stock	7,723	7,539
Loans held for sale	901,382	995,319
Loans, net	1,823,691	1,366,349
Interest receivable	10,306	8,326
Financial liabilities:
Deposits	3,176,350	2,943,561
Line of credit	25,000	25,000
Short-term subordinated debt	34,200	30,000
FHLB advances	130,315	1,612
Interest payable	4,655	2,817
Fair Value
Financial assets:
Cash and cash equivalents	352,403	359,519
Securities purchased under agreements to resell	6,954	7,043
FHLB stock	7,723	7,539
Loans held for sale	901,382	995,319
Loans, net	1,832,042	1,364,568
Interest receivable	10,306	8,326
Financial liabilities:
Deposits	3,175,515	2,943,173
Line of credit	25,000	25,000
Short-term subordinated debt	34,200	30,000
FHLB advances	130,319	1,620
Interest payable	4,655	2,817
Level 1 | Fair Value
Financial assets:
Cash and cash equivalents	352,403	359,519
Financial liabilities:
Deposits	2,480,101	2,534,605
Level 2 | Fair Value
Financial assets:
Securities purchased under agreements to resell	6,954	7,043
FHLB stock	7,723	7,539
Loans held for sale	901,382	995,319
Interest receivable	10,306	8,326
Financial liabilities:
Deposits	695,414	408,568
Line of credit	25,000	25,000
Short-term subordinated debt	34,200	30,000
FHLB advances	130,319	1,620
Interest payable	4,655	2,817
Level 3 | Fair Value
Financial assets:
Loans, net	$ 1,832,042	$ 1,364,568