ALLOWANCE FOR LOAN LOSSES: (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Allowance for Loan Losses:
Beginning balance	$ 20,068		$ 21,958		$ 19,241
Provision for loan losses	4,385	[1]	6,475	[2]	11,000	[3]
Loans charged -off	(9,450)		(13,387)		(10,414)
Recoveries	3,836		5,022		2,131
Ending Balance	18,839		20,068		21,958
Increase in provision for decrease in FDIC indemnification asset	687		1,400		2,200
Commercial
Allowance for Loan Losses:
Beginning balance	12,450		10,987		12,119
Provision for loan losses	1,053	[1]	3,144	[2]	2,400	[3]
Loans charged -off	(3,522)		(4,830)		(4,176)
Recoveries	934		3,149		644
Ending Balance	10,915		12,450		10,987
Residential
Allowance for Loan Losses:
Beginning balance	1,585		5,426		2,728
Provision for loan losses	134	[1]	629	[2]	5,196	[3]
Loans charged -off	(1,143)		(4,942)		(2,598)
Recoveries	798		472		100
Ending Balance	1,374		1,585		5,426
Consumer
Allowance for Loan Losses:
Beginning balance	3,650		3,879		3,889
Provision for loan losses	3,401	[1]	1,985	[2]	2,243	[3]
Loans charged -off	(4,785)		(3,615)		(3,640)
Recoveries	2,104		1,401		1,387
Ending Balance	4,370		3,650		3,879
Unallocated
Allowance for Loan Losses:
Beginning balance	2,383		1,666		505
Provision for loan losses	(203)	[1]	717	[2]	1,161	[3]
Loans charged -off	0		0		0
Recoveries	0		0		0
Ending Balance	$ 2,180		$ 2,383		$ 1,666

[1] Provision before increase of $687 thousand in 2014 for decrease in FDIC indemnification asset

[2] Provision before increase of $1.4 million in 2013 for increase in FDIC indemnification asset

[3] Provision before decrease of $2.2 million in 2012 for increase in FDIC indemnification asset