Goodwill and Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) $ / loans Rate	Dec. 31, 2015 USD ($) $ / loans Rate	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Servicing Asset at Amortized Cost [Line Items]
Servicing Asset at Amortized Cost	$ 20,415,000	$ 19,351,000	$ 16,688,000	$ 16,000
Servicing Asset at Amortized Cost, Additions	5,931,000	5,910,000	727,000
Valuation Allowance for Impairment of Recognized Servicing Assets, Balance	4,000	95,000	850,000	$ 0
Residential Mortgage Loans Serviced	$ 2,490,000,000	$ 2,150,000,000	1,950,000,000
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed | Rate	10.42%	11.01%
Contractually Specified Servicing Fees, Late Fees, and Ancillary Fees Earned in Exchange for Servicing Financial Assets	$ 5,800,000	$ 5,400,000	600,000
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Cost to Service Loans | $ / loans	62.75	56.61
Amortization	$ (4,958,000)	$ (4,002,000)	(919,000)
Goodwill [Roll Forward]
Beginning goodwill	139,773,000	139,773,000
Ending goodwill	150,601,000	139,773,000	139,773,000
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	90,986,000
Finite Lived Intangible Assets Removed Due To Branch Sale	0	(85,000)
Amortization	(16,850,000)	(18,892,000)
Ending balance	78,040,000	90,986,000
Finite-Lived Intangible Assets [Abstract]
Gross balance	118,041,000	115,201,000
Accumulated amortization	(60,416,000)	(43,566,000)
Carrying value	57,625,000	71,635,000
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2015	14,556,000
2016	12,220,000
2017	9,892,000
2018	7,838,000
2019	5,996,000
Other Intangible Assets, Net	57,625,000	71,635,000	89,922,000
Valuation Allowance for Impairment of Recognized Servicing Assets, Provisions (Recoveries)	(91,000)	(755,000)	850,000
1st Financial
Servicing Asset at Amortized Cost [Line Items]
Servicing Asset at Fair Value, Additions	$ 0	0	148,000
Goodwill [Roll Forward]
Useful life	3 months
Cordia Bancorp Inc.
Goodwill [Roll Forward]
Goodwill acquired	$ 10,828,000	0
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired	2,210,000	0
Capitol City Bank and Trust
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired	0	690,000
North Milwaukee State Bank
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired	240,000	0
First CornerStone Bank
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired	390,000	0
Bancorporation
Servicing Asset at Amortized Cost [Line Items]
Servicing Asset at Fair Value, Additions	$ 0	$ 0	$ 17,566,000
Goodwill [Roll Forward]
Useful life	5 years 6 months
Conventional fixed loans
Servicing Asset at Amortized Cost [Line Items]
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate | Rate	9.45%	9.31%
All loans and leases excluding conventional fixed loans [Member]
Servicing Asset at Amortized Cost [Line Items]
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate | Rate	10.45%	10.31%
Core deposits | Minimum
Goodwill [Roll Forward]
Useful life	2 years
Core deposits | Maximum
Goodwill [Roll Forward]
Useful life	9 years