Parent Company Only Financial Information - Condensed Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
ASSETS
Trading securities	$ 4,858	$ 4,576
Total Assets	2,573,821	2,285,136
Liabilities
Subordinated debentures	70,620	20,620
Total liabilities	2,362,037	2,083,223
Total shareholders' equity	211,784	201,913	$ 188,548	$ 164,911
Total liabilities and shareholders' equity	2,573,821	2,285,136
Parent Company [Member]
ASSETS
Cash	1,436	1,557
Trading securities	529	434
Investment in bank subsidiary	257,476	197,226
Investment in non-bank subsidiaries	23,324	24,345
Deferred tax asset	1,066	482
Other assets	2,666	2,106
Total Assets	286,497	226,150
Liabilities
Borrowings from subsidiary	1,400	1,350
Subordinated debentures	70,620	20,620
Other liabilities	2,693	2,267
Total liabilities	74,713	24,237
Total shareholders' equity	211,784	201,913
Total liabilities and shareholders' equity	$ 286,497	$ 226,150