Fair Value Measurements Notional Amount of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Notional Disclosures [Abstract]
Best efforts contracts and related committed IRLCs	$ 2,354	$ 1,445
Uncommitted IRLCs	208,500	87,340
FMBSs related to uncommitted IRLCs	183,000	88,000
Best efforts contracts and related mortgage loans held for sale	78,142	6,125
FMBSs related to mortgage loans held for sale	131,000	144,000
Mortgage loans held for sale covered by FMBSs	$ 148,331	$ 144,411