Loans - Recorded Investment of Individual Loan Categories (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	$ 2,262,433		$ 2,130,369
Net loans	2,247,406		2,115,532
Interest Due	6,887		6,745
Deferred Fees / (Costs)	5,291		5,617
Recorded Investment	2,274,611		2,142,731
Recorded Investment	2,259,584		2,127,894
Allowance for loan losses	(15,027)	$ (15,054)	(14,837)	$ (14,837)	$ (14,226)	$ (14,236)	$ (14,534)
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	1,139,977		1,066,199
Interest Due	3,539		3,493
Deferred Fees / (Costs)	3,784		3,757
Recorded Investment	1,147,300		1,073,449
Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	670,812		664,571
Interest Due	2,057		2,005
Deferred Fees / (Costs)	2,942		3,030
Recorded Investment	675,811		669,606
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	451,644		399,599
Interest Due	1,291		1,247
Deferred Fees / (Costs)	(1,435)		(1,170)
Recorded Investment	451,500		399,676
Owner Occupied Real Estate [Member] | Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	341,192		337,548
Interest Due	925		899
Deferred Fees / (Costs)	942		1,022
Recorded Investment	343,059		339,469
Non Owner Occupied Real Estate [Member] | Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	489,978		461,897
Interest Due	594		624
Deferred Fees / (Costs)	2,271		2,176
Recorded Investment	492,843		464,697
Residential Spec Homes [Member] | Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	3,454		5,006
Interest Due	7		8
Deferred Fees / (Costs)			(2)
Recorded Investment	3,461		5,012
Development & Spec Land Loans [Member] | Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	38,139		31,228
Interest Due	70		56
Deferred Fees / (Costs)	98		119
Recorded Investment	38,307		31,403
Commercial and Industrial [Member] | Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	267,214		230,520
Interest Due	1,943		1,906
Deferred Fees / (Costs)	473		442
Recorded Investment	269,630		232,868
Residential Mortgage [Member] | Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	529,632		508,233
Interest Due	1,546		1,492
Deferred Fees / (Costs)	2,942		3,030
Recorded Investment	534,120		512,755
Residential Construction [Member] | Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	17,423		20,611
Interest Due	31		33
Recorded Investment	17,454		20,644
Mortgage Warehousing [Member] | Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	123,757		135,727
Interest Due	480		480
Recorded Investment	124,237		136,207
Direct Installment [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	80,972		71,150
Interest Due	205		199
Deferred Fees / (Costs)	(503)		(385)
Recorded Investment	80,674		70,964
Direct Installment Purchased [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	94		119
Recorded Investment	94		119
Indirect Installment [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	186,837		153,204
Interest Due	373		345
Deferred Fees / (Costs)	177
Recorded Investment	187,387		153,549
Home Equity Loan [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan Balance	183,741		175,126
Interest Due	713		703
Deferred Fees / (Costs)	(1,109)		(785)
Recorded Investment	$ 183,345		$ 175,044