Fair Value - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Nonfinancial Assets and Liabilities [Abstract]
Outstanding balances in impaired loans	$ 49,600		$ 48,900
Foreclosed assets re-measured after initial recognition	9,300	$ 10,300
Write-downs of allowance for foreclosed assets after initial recognition	788	1,500
Noninterest gain (loss) Mortgage banking, net for changes in fair value of LHFS	(504)	3,600
Interest earned on LHFS included in Interest and fees on LHFS and LHFI	871	$ 1,100
GNMA optional repurchase loans	$ 45,000		$ 48,200
Maximum [Member]
Nonfinancial Assets and Liabilities [Abstract]
Estimated fair value of financial instruments with immediate and shorter-term maturities	90 days