INVESTMENT SECURITIES - AMORTIZED COST AND FV (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2008
Securities available for Sale - Amortized Cost
Due in one year or less	$ 174,964,000
Due from one year to five years	139,079,000
Due from five years to ten years	10,000,000
Due beyond ten years	3,493,000
Total securities	526,612,000
Securities available for Sale - Fair Value
Due in one year or less	174,798,000
Due from one year to five years	137,804,000
Due from five years to ten years	10,115,000
Due beyond ten years	3,600,000
Total securities	527,231,000
Securities held to maturity - Carrying Value
Due from one year to five years	10,570,000
Due from five years to ten years	30,069,000
Total securities	64,227,000	$ 52,864,000
Securities held to maturity - Fair Value
Due from one year to five years	10,595,000
Due from five years to ten years	30,721,000
Total securities	$ 65,133,000	$ 53,249,000
Number of Securities Held	185	179
Securities available for sale	$ 527,231,000	$ 481,275,000
Total unrealized gain	(1,265,000)	(2,294,000)	$ (3,160,000)
Private label mortgage backed security
Securities available for Sale - Amortized Cost
Securities not due at a single maturity date	3,065,000
Securities available for Sale - Fair Value
Securities not due at a single maturity date	$ 4,449,000
Securities held to maturity - Fair Value
Number of Securities Held	1
Securities available for sale	$ 4,449,000	4,777,000
Mortgage backed securities - residential
Securities available for Sale - Amortized Cost
Securities not due at a single maturity date	105,644,000
Securities available for Sale - Fair Value
Securities not due at a single maturity date	106,374,000
Securities held to maturity - Carrying Value
Securities not due at a single maturity date	151,000
Total securities	151,000	158,000
Securities held to maturity - Fair Value
Securities not due at a single maturity date	161,000
Total securities	161,000	170,000
Securities available for sale	106,374,000	73,004,000
Collateralized mortgage obligations
Securities available for Sale - Amortized Cost
Securities not due at a single maturity date	87,867,000
Securities available for Sale - Fair Value
Securities not due at a single maturity date	87,163,000
Securities held to maturity - Carrying Value
Securities not due at a single maturity date	23,437,000
Total securities	23,437,000	27,142,000
Securities held to maturity - Fair Value
Securities not due at a single maturity date	23,656,000
Total securities	23,656,000	27,268,000
Securities available for sale	87,163,000	87,654,000
Freddie Mac preferred stock
Securities available for Sale - Fair Value
Securities not due at a single maturity date	473,000
Securities held to maturity - Fair Value
Number of Securities Held				40,000
Other Than Temporary Impairment ("OTTI") charge				$ 2,100,000
Securities available for sale	473,000	483,000		$ 0
Total unrealized gain	473,000
Community Reinvestment Act mutual fund
Securities available for Sale - Amortized Cost
Securities not due at a single maturity date	2,500,000
Securities available for Sale - Fair Value
Securities not due at a single maturity date	2,455,000
Securities held to maturity - Fair Value
Securities available for sale	2,455,000	2,455,000
Corporate bonds
Securities held to maturity - Carrying Value
Total securities	40,175,000	25,058,000
Securities held to maturity - Fair Value
Total securities	40,858,000	25,307,000
Securities available for sale	$ 15,125,000	$ 15,158,000
Corporate bonds as a percentage of bank's investment portfolio	9.00%	8.00%