INCOME TAXES (Components of income tax expense (benefit)) (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current income taxes:
Federal									$ 18,699	$ 17,890	$ 13,671
State									4,692	4,140	3,103
Total current									23,391	22,030	16,774
Deferred income taxes:
Federal									516	10	554
State									(167)	(13)	254
Total deferred									349	(3)	808
Total income tax expense (benefit)	$ 6,879	$ 6,734	$ 5,008	$ 5,119	$ 6,372	$ 5,175	$ 5,014	$ 5,466	$ 23,740	$ 22,027	$ 17,582