INVESTMENTS (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Amortized cost of available-for-sale debt securities by contractual maturity
Due in one year or less	$ 25,304
Due after one year through five years	127,050
Due after five years through 10 years	662,829
Due after 10 years	190,544
Total amortized cost	1,342,089
Fair value of available-for-sale debt securities by contractual maturity
Due in one year or less	25,393
Due after one year through five years	133,778
Due after five years through 10 years	714,560
Due after 10 years	199,262
Total fair value	1,432,969	1,146,317
Amortized cost of debt securities held-to-maturity by contractual maturity
Due in one year or less	2,992
Due after one year through five years	652
Due after 10 years	8,080
Total amortized cost	11,724
Fair value of debt securities held-to-maturity by contractual maturity
Due in one year or less	3,065
Due after one year through five years	727
Due after 10 years	8,154
Total fair value	11,946
Mtge/ABS/CMO
Amortized cost of available-for-sale debt securities by contractual maturity
Total amortized cost	336,362
Fair value of available-for-sale debt securities by contractual maturity
Total fair value	$ 359,976