SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Earnings Per Share (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Net income available to common shareholders	$ 121,027	$ 73,548	$ 72,100
Weighted average number of common shares outstanding (in shares)	43,142	36,828	34,347
Effect of dilutive stock options (in shares)	6	62	108
Effect of dilutive restricted stock awards (in shares)	100	254	247
Weighted average number of common shares outstanding used to calculate diluted earnings per share (in shares)	43,248	37,144	34,702