Investment Securities - Schedule of Gross Unrealized Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Fair Value, Less than 12 months	$ 444,968	$ 240,128
Unrealized Loss, Less than 12 months	9,409	1,924
Fair Value, 12 months or more	22,199	140,866
Unrealized Loss, 12 months or more	810	3,984
Fair Value, Total	467,167	380,994
Unrealized Losses, Total	10,219	5,908
Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Fair Value, Less than 12 months	444,968	240,128
Unrealized Loss, Less than 12 months	9,409	1,924
Fair Value, 12 months or more	19,073	139,283
Unrealized Loss, 12 months or more	675	3,894
Fair Value, Total	464,041	379,411
Unrealized Losses, Total	10,084	5,818
Debt Securities | U.S. Government Agency Securities
Schedule Of Available For Sale Securities [Line Items]
Fair Value, Less than 12 months	985	15,887
Unrealized Loss, Less than 12 months	13	124
Fair Value, 12 months or more		17,921
Unrealized Loss, 12 months or more		229
Fair Value, Total	985	33,808
Unrealized Losses, Total	13	353
Debt Securities | Mortgage-backed Securities - Residential
Schedule Of Available For Sale Securities [Line Items]
Fair Value, Less than 12 months	390,595	219,756
Unrealized Loss, Less than 12 months	7,230	1,778
Fair Value, 12 months or more	19,073	121,362
Unrealized Loss, 12 months or more	675	3,665
Fair Value, Total	409,668	341,118
Unrealized Losses, Total	7,905	5,443
Debt Securities | Municipals, Tax Exempt
Schedule Of Available For Sale Securities [Line Items]
Fair Value, Less than 12 months	43,132	4,485
Unrealized Loss, Less than 12 months	2,114	22
Fair Value, Total	43,132	4,485
Unrealized Losses, Total	2,114	22
Debt Securities | Treasury Securities
Schedule Of Available For Sale Securities [Line Items]
Fair Value, Less than 12 months	10,256
Unrealized Loss, Less than 12 months	52
Fair Value, Total	10,256
Unrealized Losses, Total	52
Equity Securities
Schedule Of Available For Sale Securities [Line Items]
Fair Value, 12 months or more	3,126	1,583
Unrealized Loss, 12 months or more	135	90
Fair Value, Total	3,126	1,583
Unrealized Losses, Total	$ 135	$ 90