EMPLOYEE BENEFIT PLANS - 401(k) Employee Stock Ownership Plan (Details)	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
EMPLOYEE BENEFIT PLANS
401K, maximum employee contribution, percentage of compensation	75.00%
401K, employer contribution, approximate percentage match	48.00%	46.00%	48.00%

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration