Recent Developments Including Mergers and Acquisitions - Additional Information (Detail) (USD $)	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Jun. 30, 2014 BancFirst [Member]	Jan. 24, 2014 BancFirst [Member]	Jun. 30, 2014 BancFirst [Member] Performing [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Deposits				$ 225,600,000	$ 302,000,000
Loans					121,000,000	83,600,000
Securities					4,800,000
Other real estate					10,000
Intangibles assets, net	11,574,000	10,273,000	11,100,000		2,200,000
Goodwill	$ 44,962,000	$ 44,545,000	$ 44,545,000		$ 417,000