Investment Securities - Unrealized Losses and Fair Value of Investment Securities in Continuous Unrealized Loss Position (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	$ 7,870	$ 1,002
Available-for-sale securities, Less Than Twelve Months, Fair Value	817,564	122,799
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	10,548	12,889
Available-for-sale securities, Twelve Months or Longer, Fair Value	107,785	229,480
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	18,418	13,891
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	925,349	352,279
US Government-sponsored Enterprises Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses		0
Available-for-sale securities, Less Than Twelve Months, Fair Value		0
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses		355
Available-for-sale securities, Twelve Months or Longer, Fair Value		18,346
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total		355
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total		18,346
Corporate debt securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses		139
Available-for-sale securities, Less Than Twelve Months, Fair Value		9,860
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses		862
Available-for-sale securities, Twelve Months or Longer, Fair Value		29,139
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total		1,001
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total		38,999
Preferred Stock [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	377	232
Available-for-sale securities, Less Than Twelve Months, Fair Value	10,542	13,811
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	1,090	2,447
Available-for-sale securities, Twelve Months or Longer, Fair Value	14,761	28,109
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	1,467	2,679
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	25,303	41,920
Mutual funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses		247
Available-for-sale securities, Less Than Twelve Months, Fair Value		25,855
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses		0
Available-for-sale securities, Twelve Months or Longer, Fair Value		0
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total		247
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total		25,855
Residential mortgage-backed securities issued by GSEs
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	3,566	227
Available-for-sale securities, Less Than Twelve Months, Fair Value	536,515	49,217
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	1,098	1,758
Available-for-sale securities, Twelve Months or Longer, Fair Value	38,338	97,296
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	4,664	1,985
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	574,853	146,513
Municipal obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses		0
Available-for-sale securities, Less Than Twelve Months, Fair Value		0
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses		49
Available-for-sale securities, Twelve Months or Longer, Fair Value		4,430
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total		49
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total		4,430
Private label residential mortgage-backed securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	3,733	157
Available-for-sale securities, Less Than Twelve Months, Fair Value	226,720	24,056
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	674	964
Available-for-sale securities, Twelve Months or Longer, Fair Value	30,372	26,614
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	4,407	1,121
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	257,092	50,670
Trust preferred securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	0	0
Available-for-sale securities, Less Than Twelve Months, Fair Value	0	0
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	7,686	6,454
Available-for-sale securities, Twelve Months or Longer, Fair Value	24,314	25,546
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	7,686	6,454
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	24,314	$ 25,546
CRA investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	37
Available-for-sale securities, Less Than Twelve Months, Fair Value	24,729
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0
Available-for-sale securities, Twelve Months or Longer, Fair Value	0
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	37
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	24,729
Collateralized debt obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	49
Available-for-sale securities, Less Than Twelve Months, Fair Value	1
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0
Available-for-sale securities, Twelve Months or Longer, Fair Value	0
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	49
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	1
Commercial Mortgage Backed Securities Issued By US Government Sponsored Enterprise [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	105
Available-for-sale securities, Less Than Twelve Months, Fair Value	17,051
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0
Available-for-sale securities, Twelve Months or Longer, Fair Value	0
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	105
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	17,051
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities, Less Than Twelve Months, Aggregate Losses	3
Available-for-sale securities, Less Than Twelve Months, Fair Value	2,006
Available-for-sale securities, Twelve Months or Longer, Aggregate Losses	0
Available-for-sale securities, Twelve Months or Longer, Fair Value	0
Available-for-sale securities, Continuous Unrealized Loss Position, Aggregate Losses, Total	3
Available-for-sale securities, Continuous Unrealized Loss Position, Fair Value, Total	$ 2,006