Nature of Operations and Summary of Significant Accounting Policies (Details Textual)		12 Months Ended
		Dec. 31, 2016 USD ($) quarter step operating_segment division reporting_unit	Dec. 31, 2015 USD ($)
Number of Bank Divisions | division		13
Number of Operating Segments | operating_segment		1
Total assets		$ 9,450,600,000	$ 9,089,232,000
Gross loans	[1]	$ 5,684,463,000	5,078,681,000
Maximum Period of Original Maturity to be Included in Cash and Cash Equivalents		3 months
Federal Reserve Balance or Cash on Hand Required		$ 4,169,000
Minimum Period Past Due to Consider Loans as Delinquent		30 days
Minimum Period Past Due to Consider Loans as Non Accrual		90 days
Number of Quarters Used to Evaluate Historical Loss Experience | quarter		12
Maximum period up to which purchase price of business is allocated to assets acquired and liabilities assumed		1 year
Number of Reporting Units Subsequent to Aggregation for Goodwill Assessment | reporting_unit		1
Number of steps included in goodwill impairment test | step		2
Bank Owned Life Insurance		$ 50,451,000	$ 49,534,000
Percentage of likelihood for term more likely than not		50.00%
Period to begin developing and implementing processes and procedures for FASB Update		2 years
Maximum lease term to not recognize lease assets and liabilities		12 months
Number of Steps to Achieve Core Revenue Recognition Principal | step		5
Consumer and Other
Minimum Number of Days Delinquent to Charge Off Loans		120 days
Minimum Range
Number of years for home equity loan origination term		10 years
Minimum Range | Office Buildings
Useful life of premises and equipment		15 years
Minimum Range | Furniture, fixtures and equipment
Useful life of premises and equipment		3 years
Maximum Range
Number of years for home equity loan origination term		15 years
Maximum Range | Office Buildings
Useful life of premises and equipment		40 years
Maximum Range | Furniture, fixtures and equipment
Useful life of premises and equipment		10 years
The Foothills Bank
Total assets		$ 334,792,000
Gross loans		279,777,000
Total deposits		$ 282,198,000

[1] Includes net deferred fees, costs, premiums and discounts of $13,372,000 and $15,529,000 at December 31, 2016 and 2015, respectively.