Fair Value - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) Region	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) Region	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Nonfinancial Assets and Liabilities [Abstract]
Outstanding balances in impaired loans	$ 53,400		$ 53,400		$ 27,100
Key market regions | Region	5		5
Foreclosed assets re-measured after initial recognition			$ 16,200	$ 21,400
Write-downs of allowance for foreclosed assets after initial recognition			2,200	3,000
Noninterest gain in Mortgage banking, net for changes in fair value of LHFS	$ 58	$ 1,000	3,700	3,800
Interest earned on LHFS included in Interest and fees on LHFS and LHFI	1,200	$ 1,300	2,300	$ 2,200
GNMA optional repurchase loans	$ 39,500		$ 39,500		$ 43,900
Maximum [Member]
Nonfinancial Assets and Liabilities [Abstract]
Estimated fair value of financial instruments with immediate and shorter-term maturities			90 days