Employee Benefit and Deferred Compensation Plans (Details Textual)	12 Months Ended
	Dec. 31, 2016 USD ($) point plan shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2007 officer plan	Jan. 31, 2016 shares	Jul. 01, 2015 USD ($)
Employee Benefit and Deferred Compensation Plans (Textual) [Abstract]
Company contribution to pension benefit plan	$ 0	$ 0
Accumulated benefit obligation	$ 28,012,000	27,856,000
Retiring age limit, minimum	55 years
Retiring age limit, maximum	65 years
Eligible employee from service (in years)	15 years
Number of points for eligibility (points) | point	70
Minimum eligible age for Medicare coverage	65 years
Life insurance coverage face value	$ 5,000
Life insurance maturity age	70 years
Additional life insurance maturity age	70 years
Health care cost trend rate (percent)	5.90%
Employee deferrals (percent)	4.00%
Percentage of plan compensation as nondiscretionary contribution (percent)	5.00%
Percentage of plan compensation in excess of social security wage base (percent)	5.00%
Hours of service credited to the employees during the year	1000 hours
Employee deferrals amounts	$ 10,762,000	9,271,000	$ 7,230,000
Incentive compensation plan expense	$ 2,307,000	3,608,000	4,100,000
Number of deferred compensation plans, including deferred stock unit plan | plan	3
Number of conventional deferred compensation plans | plan	2
Company's deferred compensation plan expense	$ 1,537,000	$ 1,225,000	$ 1,383,000
Option expiration period	10 years
Option exercisable period	3 years
Granted (shares) | shares	0	0	0
Intrinsic value of options exercised	$ 8,323,000	$ 2,445,000	$ 2,519,000
Fair value of options vested in period	$ 78,000	235,000	458,000
Common shares reserved for issuance under employee benefit plans (shares) | shares	2,072,583
Heritage Financial Group
Employee Benefit and Deferred Compensation Plans (Textual) [Abstract]
Loans outstanding related to employee stock ownership plan acquired						$ 2,839,000
Retiree Health Benefits
Employee Benefit and Deferred Compensation Plans (Textual) [Abstract]
Company contribution to pension benefit plan	$ 152,000	278,000
Expected company contributions	$ 247,000
Supplemental Employee Retirement Plans, Defined Benefit
Employee Benefit and Deferred Compensation Plans (Textual) [Abstract]
Number of plans assumed in acquisition | plan				4
Number of officers provided for via plan | officer				4
Expiration period of benefits payable subsequent to retirement (in years)	15 years
Supplemental executive retirement liabilities totaled	$ 3,543,000	3,364,000
Minimum | Other equity securities
Employee Benefit and Deferred Compensation Plans (Textual) [Abstract]
Equity income strategy (percent)	65.00%
Minimum | Debt Securities
Employee Benefit and Deferred Compensation Plans (Textual) [Abstract]
Equity income strategy (percent)	25.00%
Maximum | Other equity securities
Employee Benefit and Deferred Compensation Plans (Textual) [Abstract]
Equity income strategy (percent)	75.00%
Maximum | Debt Securities
Employee Benefit and Deferred Compensation Plans (Textual) [Abstract]
Equity income strategy (percent)	35.00%
Performance- Based Restricted Stock(1)
Employee Benefit and Deferred Compensation Plans (Textual) [Abstract]
Compensation expense	$ 3,117,000	3,884,000	3,647,000
Service period (in years)	1 year
Target performance level, allowable variance above and below target	5.00%
Performance-based restricted stock based on the target level of performance goals (shares) | shares					61,700
Cancelled (shares) | shares	9,655
Shares awarded, other than options (shares) | shares	52,045
Time- Based Restricted Stock
Employee Benefit and Deferred Compensation Plans (Textual) [Abstract]
Cancelled (shares) | shares	18,960
Unrecognized stock-based compensation expense	$ 1,129,000
Weighted average period over which unrecognized expense is expected to be recognized (in years)	1 year 5 months 12 days
Stock compensation plan
Employee Benefit and Deferred Compensation Plans (Textual) [Abstract]
Compensation expense	$ 0	$ 73,000	$ 262,000
Unrecognized stock-based compensation expense	$ 0