Fair Value (Financial instruments Measured at Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	$ 1,821,697	$ 1,453,132
Foreclosed properties	1,811	2,424
Government-sponsored enterprise securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	67,022	70,206
Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,709,811	1,337,706
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Presold mortgages in process of settlement	31,869	42,271
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring | Government-sponsored enterprise securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring | Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent loans	0	0
Foreclosed properties	0	0
Significant Other Observable Inputs (Level 2) | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,821,697	1,453,132
Presold mortgages in process of settlement	0	0
Significant Other Observable Inputs (Level 2) | Recurring | Government-sponsored enterprise securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	67,022	70,206
Significant Other Observable Inputs (Level 2) | Recurring | Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,709,811	1,337,706
Significant Other Observable Inputs (Level 2) | Recurring | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	44,864	45,220
Significant Other Observable Inputs (Level 2) | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent loans	0	0
Foreclosed properties	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent loans	22,176	16,000
Foreclosed properties	1,484	1,484
Significant Unobservable Inputs (Level 3) | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Presold mortgages in process of settlement	0	0
Significant Unobservable Inputs (Level 3) | Recurring | Government-sponsored enterprise securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | Recurring | Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | Recurring | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	0	0
Significant Unobservable Inputs (Level 3) | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent loans	28,082	22,142
Foreclosed properties	1,484	1,484
Estimated Fair Value | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,821,697	1,453,132
Presold mortgages in process of settlement	31,869	42,271
Estimated Fair Value | Recurring | Government-sponsored enterprise securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	67,022	70,206
Estimated Fair Value | Recurring | Mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	1,709,811	1,337,706
Estimated Fair Value | Recurring | Corporate bonds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	44,864	45,220
Estimated Fair Value | Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Collateral dependent loans	28,082	22,142
Foreclosed properties	$ 1,484	$ 1,484