Fair Value Measurements Notional Amount of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Notional Amount of Derivatives [Abstract]
Best efforts contracts and related committed IRLCs	$ 1,820	$ 1,184
Uncommitted IRLCs	36,407	25,854
FMBSs related to uncommitted IRLCs	38,000	26,000
Best efforts contracts and related mortgage loans held for sale	3,969	25,441
FMBSs related to mortgage loans held for sale	50,766	44,000
Mortgage loans held for sale covered by FMBSs	$ 50,962	$ 44,524