Fair Value Measurements - Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Carrying Value
Financial Assets:
Cash and cash equivalents	$ 162,913	$ 228,568
Investment securities available for sale	961,092	952,312
Loans held for sale	3,808	5,533
Loans receivable, net	3,804,836	3,731,708
Accrued interest receivable	14,940	14,446
Derivative assets - interest rate swaps	28,075	8,318
Equity security	96	148
Financial Liabilities:
Noninterest deposits, interest bearing demand deposits, money market accounts and savings accounts	4,091,959	4,058,098
Certificate of deposit accounts	525,989	524,578
Securities sold under agreement to repurchase	11,792	20,169
Junior subordinated debentures	20,668	20,595
Accrued interest payable	154	199
Derivative liabilities - interest rate swaps	28,075	8,318
Fair Value
Financial Assets:
Cash and cash equivalents	0	228,568
Investment securities available for sale	961,092	952,312
Loans held for sale	3,935	5,704
Loans receivable, net	3,851,281	3,791,557
Accrued interest receivable	14,940	14,446
Derivative assets - interest rate swaps	28,075	8,318
Equity security	96	148
Financial Liabilities:
Noninterest deposits, interest bearing demand deposits, money market accounts and savings accounts	4,091,959	4,058,098
Certificate of deposit accounts	530,580	529,679
Securities sold under agreement to repurchase	11,792	20,169
Junior subordinated debentures	17,750	20,000
Accrued interest payable	154	199
Derivative liabilities - interest rate swaps	28,075	8,318
Fair Value | Level 1
Financial Assets:
Cash and cash equivalents	162,913	228,568
Investment securities available for sale	850	0
Loans held for sale	0	0
Loans receivable, net	0	0
Accrued interest receivable	1	79
Derivative assets - interest rate swaps	0	0
Equity security		148
Financial Liabilities:
Noninterest deposits, interest bearing demand deposits, money market accounts and savings accounts	4,091,959	4,058,098
Certificate of deposit accounts	0	0
Securities sold under agreement to repurchase	11,792	20,169
Junior subordinated debentures	0	0
Accrued interest payable	69	95
Derivative liabilities - interest rate swaps	0	0
Fair Value | Level 2
Financial Assets:
Cash and cash equivalents	0	0
Investment securities available for sale	960,242	952,312
Loans held for sale	0	0
Loans receivable, net	0	0
Accrued interest receivable	3,851	3,668
Derivative assets - interest rate swaps	28,075	8,318
Equity security	0	0
Financial Liabilities:
Noninterest deposits, interest bearing demand deposits, money market accounts and savings accounts	0	0
Certificate of deposit accounts	530,580	529,679
Securities sold under agreement to repurchase	0	0
Junior subordinated debentures	0	0
Accrued interest payable	59	64
Derivative liabilities - interest rate swaps	28,075	8,318
Fair Value | Level 3
Financial Assets:
Cash and cash equivalents	0	0
Investment securities available for sale	0	0
Loans held for sale	3,935	5,704
Loans receivable, net	3,851,281	3,791,557
Accrued interest receivable	11,088	10,699
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	17,750	20,000
Accrued interest payable	26	40
Derivative liabilities - interest rate swaps	$ 0	$ 0