Fair Value Measurement - Estimates Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Carrying Amount [Member]
Financial Assets
Cash and due from banks	$ 128,170	$ 86,685
Trading securities	7,071	6,451
Securities available-for-sale	1,241,176	1,403,069
Securities held-to-maturity	1,067,967	1,012,930
Net loans	6,205,762	5,024,132
Loans held for sale	17,315	7,899
Other assets - interest rate derivatives	5,596	1,893
Accrued interest receivable	28,299	25,759
Financial Liabilities
Deposits	7,040,879	6,066,299
Federal Home Loan Bank borrowings	968,946	1,041,750
Other borrowings	199,376	81,356
Subordinated debt and junior subordinated debt	163,598
Subordinated debt and junior subordinated debt owed to unconsolidated subsidiary trust		106,196
Other liabilities - interest rate derivatives	5,199	1,991
Accrued interest payable	2,204	1,715
Fair Value Estimate [Member]
Financial Assets
Cash and due from banks	128,170	86,685
Trading securities	7,071	6,451
Securities available-for-sale	1,241,176	1,403,069
Securities held-to-maturity	1,076,790	1,038,207
Net loans	6,073,558	4,936,236
Loans held for sale	17,315	7,899
Other assets - interest rate derivatives	5,596	1,893
Accrued interest receivable	28,299	25,759
Financial Liabilities
Deposits	7,052,501	6,075,433
Federal Home Loan Bank borrowings	974,430	1,041,752
Other borrowings	199,385	81,361
Subordinated debt and junior subordinated debt	134,859
Subordinated debt and junior subordinated debt owed to unconsolidated subsidiary trust		79,681
Other liabilities - interest rate derivatives	5,199	1,991
Accrued interest payable	2,204	1,715
Investments Measured At Net Asset Value [Member]
Financial Assets
Trading securities	1,438	1,225
Cash and due from banks	128,170	86,685	$ 94,002	$ 95,551
Trading securities	7,071	6,451
Securities available-for-sale	1,241,176	1,403,069
Securities held-to-maturity	1,067,967	1,012,930
Net loans	6,205,762	5,024,132
Loans held for sale	17,315	7,899
Other assets - interest rate derivatives	5,596	1,893
Accrued interest receivable	28,299	25,759
Financial Liabilities
Deposits	7,040,879	6,066,299
Federal Home Loan Bank borrowings	968,946	1,041,750
Other borrowings	199,376	81,356
Subordinated debt and junior subordinated debt	163,598	106,196
Subordinated debt and junior subordinated debt owed to unconsolidated subsidiary trust	137,559
Other liabilities - interest rate derivatives	5,199	1,991
Accrued interest payable	2,204	1,715
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Financial Assets
Cash and due from banks	128,170	86,685
Trading securities	5,633	5,226
Securities available-for-sale	2,938	2,735
Accrued interest receivable	28,299	25,759
Financial Liabilities
Deposits	5,545,057	4,508,461
Other borrowings	197,164	78,682
Accrued interest payable	2,204	1,715
Significant Other Observable Inputs (Level 2) [Member]
Financial Assets
Securities available-for-sale	1,238,238	1,400,334
Securities held-to-maturity	1,076,189	1,037,490
Loans held for sale	17,315	7,899
Other assets - interest rate derivatives	5,596	1,893
Financial Liabilities
Deposits	1,507,444	1,566,972
Federal Home Loan Bank borrowings	974,430	1,041,752
Other borrowings	2,221	2,679
Subordinated debt and junior subordinated debt	134,859
Subordinated debt and junior subordinated debt owed to unconsolidated subsidiary trust		79,681
Other liabilities - interest rate derivatives	5,199	1,991
Significant Unobservable Inputs (Level 3) [Member]
Financial Assets
Securities held-to-maturity	601	717
Net loans	$ 6,073,558	$ 4,936,236