NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Post-retirement Benefits
Pension expense	$ 9,300
Unamortized actuarial loss	8,000
Liability related to underfunded status of defined benefit pension plan	$ 4,600		$ 4,600
Future expected benefits payment
2017		$ 1,749
2018		1,669
2019		1,597
2020		1,538
2021		1,479
Next 5 years		6,532
Fisher SERP | Fisher
Post-retirement Benefits
Estimated projected benefit obligation		21,500
Benefit payments		1,700	1,500
Periodic pension expense		900	900
Actuarial gain		$ 100	$ 1,000
Discount rate for projected benefit obligation (as a percent)	4.11%	3.89%	4.11%
Fisher SERP | Fisher | Accrued expenses
Post-retirement Benefits
Estimated projected benefit obligation		$ 1,700
Fisher SERP | Fisher | Other long-term liabilities
Post-retirement Benefits
Estimated projected benefit obligation		$ 19,800