INCOME TAXES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reconciliation of income tax expense reported to amount computed by applying the U.S. federal tax rate
Provision for income taxes at the statutory rate of 35%	$ 19,127	$ 18,348	$ 34,707	$ 33,045
Tax-exempt interest income	(1,054)	(1,048)	(2,016)	(2,082)
Dividends received deduction	(535)	(533)	(1,112)	(1,131)
ESOP dividends paid deduction	(238)	(220)	(458)	(421)
Other items, net	165	151	259	309
Total tax expense	$ 17,465	$ 16,698	$ 31,380	$ 29,720
Reconciliation of income tax expense rate to the U.S. federal tax rate
U.S. federal tax rate (as a percent)	35.00%	35.00%	35.00%	35.00%
Effective rate reduction due to tax exempt interest income (as a percent)	(2.00%)	(2.00%)	(2.00%)	(2.00%)
Effective rate reduction due to dividend received (as a percent)	(1.00%)	(1.00%)	(1.00%)	(1.00%)
Effective rate reduction due to special dividend paid to ESOP (as a percent)		(1.00%)		(1.00%)
Effective tax rates (as a percent)	32.00%	31.00%	32.00%	31.00%