EMPLOYEE BENEFIT PLANS (Settlement distributions and expense) (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Distributions and pension settlement expense
Pension settlement expense, pre-tax		$ 3,229	$ 3,202	$ 6,595
Nonunion Defined Benefit Pension Plan
Distributions and pension settlement expense
Pension settlement distributions		16,515	20,622	57,518
Pension settlement expense, pre-tax		$ 3,023	$ 3,202	$ 5,880
Pension settlement expense per diluted share, net of taxes		$ 0.07	$ 0.07	$ 0.14
Lump-sum distributions				$ 32,100
Premium paid to purchase nonparticipating annuity contract	$ 25,400			25,400
Supplemental Benefit Plan
Distributions and pension settlement expense
Pension settlement distributions		$ 246	$ 1,941	853
Pension settlement expense, pre-tax		$ 206		$ 715
Pension settlement expense per diluted share, net of taxes		$ 0.01		$ 0.02
Period of delay for pension settlement distribution to key employees			6 months