INCOME TAXES - Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current
Federal	$ 28,699	$ 29,117	$ 19,309
State	5,176	5,325	2,959
Total	33,875	34,442	22,268
Deferred
Federal	32,159	14,571	8,862
State	5,436	2,348	1,398
Total	37,595	16,919	10,260
Items charged or credited directly to stockholders' equity
Federal		1,218	(33)
State		192	(5)
Total		1,410	(38)
Income tax expense	71,470	$ 52,771	$ 32,490
Decrease in income tax expense from recognized excess tax benefits	$ 600