Securities (Detail) - Securities In An Unrealized Loss Position $ in Thousands	Dec. 31, 2015 USD ($) security	Dec. 31, 2014 USD ($) security
Securities Available-for-Sale [Abstract]
Number of Securities \| security	252	195
Fair Value - Less Than 12 Months	$ 428,035	$ 65,694
Unrealized Losses - Less Than 12 Months	4,897	579
Fair Value - 12 Months or Longer	337,516	402,418
Unrealized Losses - 12 Months or Longer	22,534	22,656
Fair Value - Total	765,551	468,112
Unrealized Losses - Total	$ 27,431	$ 23,235
Securities Held-to-Maturity [Abstract]
Number of Securities \| security	19
Fair Value - Less than 12 Months	$ 20,054
Unrealized Losses - Less Than 12 Months	3,098
Fair Value - 12 Months or Longer	0
Unrealized Losses - 12 Months or Longer	0
Fair Value - Total	20,054
Unrealized Losses - Total	$ 3,098
US Treasury Securities
Securities Available-for-Sale [Abstract]
Number of Securities \| security	4
Fair Value - Less Than 12 Months	$ 7,946
Unrealized Losses - Less Than 12 Months	35
Fair Value - 12 Months or Longer	0
Unrealized Losses - 12 Months or Longer	0
Fair Value - Total	7,946
Unrealized Losses - Total	$ 35
U.S. Agency Securities
Securities Available-for-Sale [Abstract]
Number of Securities \| security	10	1
Fair Value - Less Than 12 Months	$ 30,620	$ 1,943
Unrealized Losses - Less Than 12 Months	169	10
Fair Value - 12 Months or Longer	0	0
Unrealized Losses - 12 Months or Longer	0	0
Fair Value - Total	30,620	1,943
Unrealized Losses - Total	$ 169	$ 10
Collateralized Mortgage Obligations
Securities Available-for-Sale [Abstract]
Number of Securities \| security	133	87
Fair Value - Less Than 12 Months	$ 309,787	$ 61,321
Unrealized Losses - Less Than 12 Months	3,110	559
Fair Value - 12 Months or Longer	257,362	284,327
Unrealized Losses - 12 Months or Longer	5,975	6,423
Fair Value - Total	567,149	345,648
Unrealized Losses - Total	$ 9,085	$ 6,982
Other Mortgage Backed Securities
Securities Available-for-Sale [Abstract]
Number of Securities \| security	27	11
Fair Value - Less Than 12 Months	$ 63,028	$ 1,113
Unrealized Losses - Less Than 12 Months	427	1
Fair Value - 12 Months or Longer	31,980	39,043
Unrealized Losses - 12 Months or Longer	444	309
Fair Value - Total	95,008	40,156
Unrealized Losses - Total	$ 871	$ 310
Municipal Securities
Securities Available-for-Sale [Abstract]
Number of Securities \| security	68	91
Fair Value - Less Than 12 Months	$ 8,135	$ 1,317
Unrealized Losses - Less Than 12 Months	65	9
Fair Value - 12 Months or Longer	24,227	53,987
Unrealized Losses - 12 Months or Longer	245	1,009
Fair Value - Total	32,362	55,304
Unrealized Losses - Total	$ 310	$ 1,018
Trust-preferred Collateralized Debt Obligations
Securities Available-for-Sale [Abstract]
Number of Securities \| security	8	4
Fair Value - Less Than 12 Months	$ 8,034	$ 0
Unrealized Losses - Less Than 12 Months	971	0
Fair Value - 12 Months or Longer	21,642	22,791
Unrealized Losses - 12 Months or Longer	15,821	14,880
Fair Value - Total	29,676	22,791
Unrealized Losses - Total	$ 16,792	$ 14,880
Equity Securities
Securities Available-for-Sale [Abstract]
Number of Securities \| security	2	1
Fair Value - Less Than 12 Months	$ 485	$ 0
Unrealized Losses - Less Than 12 Months	120	0
Fair Value - 12 Months or Longer	2,305	2,270
Unrealized Losses - 12 Months or Longer	49	35
Fair Value - Total	2,790	2,270
Unrealized Losses - Total	$ 169	$ 35

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