LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Fixed-rate and Adjustable-Rate Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fixed-rate (term to maturity):
Maturing in one year or less	$ 115,571	$ 122,313
Maturing after one year through three years	184,707	143,322
Maturing after three years through five years	180,449	187,279
Maturing after five years through ten years	240,742	209,869
Maturing after ten years	572,793	439,004
Total fixed-rate loans	(1,294,262)	(1,101,787)
Adjustable-Rate (term to rate adjustment):
Maturing or repricing in one year or less	1,468,316	1,390,579
Maturing or repricing after one year through three years	416,433	279,791
Maturing or repricing after three years through five years	566,371	541,529
Maturing or repricing after five years through ten years	87,506	99,503
Maturing or repricing after ten years	932	5,256
Total adjustable-rate loans	(2,539,558)	(2,316,658)
Total loans outstanding	$ 3,833,820	$ 3,418,445