Income Taxes - Summary of Significant Components of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Loan loss reserve	$ 11,250	$ 9,397
Tax credit carryforwards	65,216	37,353
NOL carryforward	7,317	4,030
Stock-based compensation	684	436
Deferred compensation	91	91
Securities available for sale	8,880	1,563
Other real estate	250	269
Basis difference in assumed liabilities	338	1,701
Other	373	355
Total deferred tax assets	94,399	55,195
Deferred tax liabilities:
Fixed assets	6,546	5,867
Deferred loan costs	5,157	4,414
Amortizable costs	1,477	1,697
State tax credits	1,155	669
Investments in tax credit entities	28,097	25,789
Other	776	170
Total deferred tax liabilities	43,208	38,606
Net deferred tax assets	$ 51,191	$ 16,589