RETIREMENT ANNUITY AND GUARANTEED CONTINUOUS EMPLOYMENT PLANS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Change in benefit obligations
Benefit obligations at beginning of year	$ 851,948	$ 777,521
Service cost	17,331	15,371	12,755
Interest cost	44,161	42,730	43,097
Plan participants' contributions	365	365
Actuarial loss	121,800	57,707
Benefits paid	(40,345)	(38,839)
Settlement/curtailment	(2,434)	(4,553)
Currency translation	(847)	1,646
Benefit obligations at end of year	991,979	851,948	777,521
Change in plan assets
Fair value of plan assets at beginning of year	726,474	636,758
Actual return on plan assets	29,470	83,750
Employer contributions	33,994	44,766
Plan participants' contributions	365	365
Benefits paid	(37,960)	(36,529)
Settlement	(2,415)	(4,355)
Currency translation	(472)	1,719
Fair value of plan assets at end of year	749,456	726,474	636,758
Net amount recognized
Funded status at end of year	(242,523)	(125,474)
Unrecognized net loss	408,474	281,431
Unrecognized prior service cost	(515)	(843)
Unrecognized transition assets, net	41	64
Net amount recognized	$ 165,477	$ 155,178