Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	$ 1,115,905	$ 1,032,868
Equity securities	1,765	1,890
U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	45,131	54,157
Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	1,001,443	920,007
Municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	190	987
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	64,600	53,467
Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	4,541	4,250
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	45,131	54,157
Equity securities	1,765	1,890
Derivative assets	0	0
Derivative liabilities	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	1,070,774	978,711
Equity securities	0	0
Derivative assets	8,740	1,342
Derivative liabilities	22,676	3,944
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	0	0
Equity securities	0	0
Derivative assets	0	0
Derivative liabilities	0	0
Measured on recurring basis
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	1,115,905	1,032,868
Equity securities	1,765	1,890
Derivative assets	8,740	1,342
Assets	1,126,410	1,036,100
Derivative liabilities	22,676	3,944
Measured on recurring basis | U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	45,131	54,157
Measured on recurring basis | Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	1,001,443	920,007
Measured on recurring basis | Municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	190	987
Measured on recurring basis | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	64,600	53,467
Measured on recurring basis | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	4,541	4,250
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	45,131	54,157
Equity securities	1,765	1,890
Derivative assets	0	0
Assets	46,896	56,047
Derivative liabilities	0	0
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	45,131	54,157
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	0	0
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	0	0
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	0	0
Measured on recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	0	0
Measured on recurring basis | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	1,070,774	978,711
Equity securities	0	0
Derivative assets	8,740	1,342
Assets	1,079,514	980,053
Derivative liabilities	22,676	3,944
Measured on recurring basis | Significant Other Observable Inputs (Level 2) | U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	0	0
Measured on recurring basis | Significant Other Observable Inputs (Level 2) | Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	1,001,443	920,007
Measured on recurring basis | Significant Other Observable Inputs (Level 2) | Municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	190	987
Measured on recurring basis | Significant Other Observable Inputs (Level 2) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	64,600	53,467
Measured on recurring basis | Significant Other Observable Inputs (Level 2) | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	4,541	4,250
Measured on recurring basis | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	0	0
Equity securities	0
Derivative assets	0	0
Assets	0	0
Derivative liabilities	0	0
Measured on recurring basis | Significant Unobservable Inputs (Level 3) | U.S. government and agency obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	0	0
Measured on recurring basis | Significant Unobservable Inputs (Level 3) | Mortgage-backed securities and collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	0	0
Measured on recurring basis | Significant Unobservable Inputs (Level 3) | Municipal obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	0	0
Measured on recurring basis | Significant Unobservable Inputs (Level 3) | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	0	0
Measured on recurring basis | Significant Unobservable Inputs (Level 3) | Trust preferred securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total debt securities available for sale	$ 0	$ 0