OPERATING LEASES (Details) $ in Thousands	1 Months Ended							12 Months Ended
	Dec. 31, 2013 item	May 31, 2013	Sep. 30, 2012 item	Feb. 28, 2011	Apr. 30, 2010 item	Apr. 30, 2008	Sep. 30, 2005	Dec. 31, 2016 USD ($) item	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2011
OPERATING LEASES
Number of operating leases | item								7
Additional number of operating leases acquired | item								3
Future minimum payments, by year and in the aggregate, under the initial terms of the operating lease agreements
2017								$ 722
2018								587
2019								517
2020								467
2021								476
Thereafter								3,609
Total								6,378
Rent Expenses
Rent expense for all operating leases								$ 1,053	$ 985	$ 885
Birmingham
OPERATING LEASES
Operating lease term							66 months
Option to renew additional lease term							5 years
Additional period for operating lease									3 years		3 years
Manistique
OPERATING LEASES
Maximum number of additional lease terms for which the lease may be extended | item					4
Traverse City
OPERATING LEASES
Operating lease term								36 months
Option to renew additional lease term								36 months
Maximum number of additional lease terms for which the lease may be extended | item								2
Marquette
OPERATING LEASES
Operating lease term	15 years			5 years
Additional period for operating lease	4 years
Maximum number of additional lease terms for which the lease may be extended | item	2
Negaunee
OPERATING LEASES
Operating lease term			5 years
Additional period for operating lease			5 years
Maximum number of additional lease terms for which the lease may be extended | item			1
Ishpeming
OPERATING LEASES
Operating lease term						5 years
Option to renew additional lease term		5 years