Fair Value - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) Region	Dec. 31, 2014 USD ($)
Nonfinancial Assets and Liabilities [Abstract]
Outstanding balances in impaired loans	$ 26,500	$ 47,100
Key market regions | Region	5
Foreclosed assets measured at fair value	$ 33,400	37,400
Allowance for possible loan losses, Charge-offs for foreclosed assets upon initial recognition	7,900	13,900
Foreclosed assets re-measured after initial recognition	44,500	48,700
Write-downs of allowance for foreclosed assets after initial recognition	$ 2,900	7,700
Estimated fair value of financial instruments with immediate and shorter-term maturities maximum	90 days
Noninterest gain (loss) Mortgage banking, net for changes in fair value of LHFS	$ (857)	2,000
Interest earned on LHFS included in Interest and fees on LHFS and LHFI	$ 4,700	$ 1,100