Segment Reporting - Schedule of Financial Information with Respect to Company's Reportable Business Segments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net interest income	$ 29,320	$ 28,238	$ 87,134	$ 84,846
Provision for loan losses	2,920	6,540	10,008	26,647
Noninterest income	12,288	9,831	35,032	45,970
Noninterest expense
Salaries and employee benefits	14,412	13,766	41,599	37,337
Equipment and occupancy expenses	3,149	3,340	9,058	9,555
Data processing and telecommunications expenses	3,072	2,599	8,478	7,429
Other expenses	8,116	8,320	25,186	35,358
Total noninterest expense	28,749	28,810	84,321	89,679
Income before income tax expense	9,939	2,719	27,837	14,490
Income tax expense	3,262	816	9,197	4,727
Net income	6,677	1,903	18,640	9,763
Less preferred stock dividends	443	827	1,326	2,459
Net income available to common shareholders	6,234	1,076	17,314	7,304
Total assets	2,818,502	2,949,383	2,818,502	2,949,383	3,019,052
Stockholders' equity	290,356	299,206	290,356	299,206	279,017
Retail Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	28,089	27,953	84,372	84,243
Provision for loan losses	2,920	6,540	10,008	26,647
Noninterest income	7,054	6,091	20,333	37,749
Noninterest expense
Salaries and employee benefits	10,799	11,446	32,314	32,435
Equipment and occupancy expenses	3,029	3,190	8,575	9,250
Data processing and telecommunications expenses	2,908	2,510	8,013	7,222
Other expenses	7,473	8,706	22,807	34,470
Total noninterest expense	24,209	25,852	71,709	83,377
Income before income tax expense	8,014	1,652	22,988	11,968
Income tax expense	2,588	443	7,500	3,845
Net income	5,426	1,209	15,488	8,123
Less preferred stock dividends	443	827	1,326	2,459
Net income available to common shareholders	4,983	382	14,162	5,664
Total assets	2,707,200	2,947,004	2,707,200	2,947,004
Stockholders' equity	250,863	299,221	250,863	299,221
Mortgage Banking [Member]
Segment Reporting Information [Line Items]
Net interest income	1,231	285	2,762	603
Noninterest income	5,234	3,740	14,699	8,221
Noninterest expense
Salaries and employee benefits	3,613	2,320	9,285	4,902
Equipment and occupancy expenses	120	150	483	305
Data processing and telecommunications expenses	164	89	465	207
Other expenses	643	9,105	2,379	888
Total noninterest expense	4,540	2,958	12,612	6,302
Income before income tax expense	1,925	1,067	4,849	2,522
Income tax expense	674	373	1,697	882
Net income	1,251	694	3,152	1,640
Net income available to common shareholders	1,251	694	3,152	1,640
Total assets	111,302	2,379	111,302	2,379
Stockholders' equity	$ 39,493	$ (15)	$ 39,493	$ (15)