BUSINESS COMBINATIONS - fair value of the assets purchased, including goodwill, and liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 03, 2016	Mar. 11, 2016	Dec. 31, 2015
Assets:
Loans, net		$ 314,000
Goodwill	$ 64,649			$ 25,211
Other assets			$ 417,000
Liabilities:
Deposits		63,000
The Bank shares Inc [Member] | Measurement Period Adjustments [Member]
Assets:
Cash			0
Investment securities			95
Loans, net			(2,112)
Fixed assets			(628)
Core deposit intangibles			0
Goodwill			1,647
Other assets			998
Total assets acquired			0
Liabilities:
Deposits			0
Other liabilities			0
Total liabilities assumed			0
The Bank shares Inc [Member] | Scenario, Previously Reported [Member]
Assets:
Cash			28,243
Investment securities			66,912
Loans, net			268,249
Fixed assets			7,801
Core deposit intangibles			3,375
Goodwill			29,985
Other assets			12,879
Total assets acquired			417,444
Liabilities:
Deposits			337,341
Other liabilities			2,492
Total liabilities assumed			339,833
The Bank shares Inc [Member] | Restatement Adjustment [Member]
Assets:
Cash			28,243
Investment securities			67,007
Loans, net			266,137
Fixed assets			7,173
Core deposit intangibles			3,375
Goodwill			31,632
Other assets			13,877
Total assets acquired			417,444
Liabilities:
Deposits			337,341
Other liabilities			2,492
Total liabilities assumed			$ 339,833
BMO Harris Bank [Member] | Measurement Period Adjustments [Member]
Assets:
Cash		0
Loans, net		0
Fixed assets		0
Core deposit intangibles		(135)
Goodwill		163
Other assets		(28)
Total assets acquired		0
Liabilities:
Deposits		0
Other liabilities		0
Total liabilities assumed		0
BMO Harris Bank [Member] | Scenario, Previously Reported [Member]
Assets:
Cash		234,094
Loans, net		62,671
Fixed assets		3,715
Core deposit intangibles		5,223
Goodwill		7,645
Other assets		952
Total assets acquired		314,300
Liabilities:
Deposits		314,248
Other liabilities		52
Total liabilities assumed		314,300
BMO Harris Bank [Member] | Restatement Adjustment [Member]
Assets:
Cash		234,094
Loans, net		62,671
Fixed assets		3,715
Core deposit intangibles		5,088
Goodwill		7,808
Other assets		924
Total assets acquired		314,300
Liabilities:
Deposits		314,248
Other liabilities		52
Total liabilities assumed		$ 314,300