Fair Value Measurements - Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financial Liabilities:
Certificate of deposit accounts	$ 524,578	$ 466,892
Reported Value Measurement
Financial Assets:
Cash and cash equivalents	228,568	161,910
Investment securities available for sale	952,312	976,095
Federal Home Loan Bank stock		6,076
Loans held for sale	5,533	1,555
Total loans receivable, net	3,731,708	3,619,118
Accrued interest receivable	14,446	15,403
Derivative assets - interest rate swaps	8,318	5,095
Equity security	148	114
Financial Liabilities:
Noninterest deposits, interest bearing demand deposits, money market accounts and savings accounts	4,058,098	3,965,510
Certificate of deposit accounts	524,578	466,892
Securities sold under agreement to repurchase	20,169	31,487
Junior subordinated debentures	20,595	20,302
Accrued interest payable	199	191
Derivative liabilities - interest rate swaps	8,318	5,095
Fair Value
Financial Assets:
Cash and cash equivalents	228,568	161,910
Investment securities available for sale	952,312	976,095
Loans held for sale	5,704	1,605
Total loans receivable, net	3,791,557	3,613,076
Accrued interest receivable	14,446	15,403
Derivative assets - interest rate swaps	8,318	5,095
Equity security	148	114
Financial Liabilities:
Noninterest deposits, interest bearing demand deposits, money market accounts and savings accounts	4,058,098	3,965,510
Certificate of deposit accounts	529,679	470,222
Securities sold under agreement to repurchase	20,169	31,487
Junior subordinated debentures	20,000	20,500
Accrued interest payable	199	191
Derivative liabilities - interest rate swaps	8,318	5,095
Fair Value | Level 1
Financial Assets:
Cash and cash equivalents	228,568	161,910
Investment securities available for sale	0	15,936
Loans held for sale	0	0
Total loans receivable, net	0	0
Accrued interest receivable	79	68
Derivative assets - interest rate swaps	0	0
Equity security		114
Financial Liabilities:
Noninterest deposits, interest bearing demand deposits, money market accounts and savings accounts	4,058,098	3,965,510
Certificate of deposit accounts	0	0
Securities sold under agreement to repurchase	20,169	31,487
Junior subordinated debentures	0	0
Accrued interest payable	95	63
Derivative liabilities - interest rate swaps	0	0
Fair Value | Level 2
Financial Assets:
Cash and cash equivalents	0	0
Investment securities available for sale	952,312	960,159
Loans held for sale	0	1,605
Total loans receivable, net	0	0
Accrued interest receivable	3,668	4,091
Derivative assets - interest rate swaps	8,318	5,095
Equity security	0	0
Financial Liabilities:
Noninterest deposits, interest bearing demand deposits, money market accounts and savings accounts	0	0
Certificate of deposit accounts	529,679	470,222
Securities sold under agreement to repurchase	0	0
Junior subordinated debentures	0	0
Accrued interest payable	64	81
Derivative liabilities - interest rate swaps	8,318	5,095
Fair Value | Level 3
Financial Assets:
Cash and cash equivalents	0	0
Investment securities available for sale	0	0
Loans held for sale	5,704	0
Total loans receivable, net	3,791,557	3,613,076
Accrued interest receivable	10,699	11,244
Derivative assets - interest rate swaps	0	0
Equity security	0	0
Financial Liabilities:
Noninterest deposits, interest bearing demand deposits, money market accounts and savings accounts	0	0
Certificate of deposit accounts	0	0
Securities sold under agreement to repurchase	0	0
Junior subordinated debentures	20,000	20,500
Accrued interest payable	40	47
Derivative liabilities - interest rate swaps	$ 0	$ 0