CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY - Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (27,516)	$ (11,761)
Adjustments to reconcile net loss to net cash provided by operating activities:
Net cash provided by operating activities	22,569	25,277
Cash flows from investing activities:
Net cash provided by investing activities	139,210	96,279
Cash flows from financing activities:
Proceeds from exercise of stock options	643	266
Proceeds from issuance of common stock	0	57,151
Payment of dividends on preferred stock	(3,239)	(3,242)
Payment of common dividends	(662)	(2,880)
Net cash used in financing activities	(109,289)	(50,820)
Net increase in cash and cash equivalents	52,490	70,736
Cash and cash equivalents, beginning of year	152,964	82,228
Cash and cash equivalents, end of year	205,454	152,964
Parent Company
Cash flows from operating activities:
Net loss	(27,516)	(11,761)
Adjustments to reconcile net loss to net cash provided by operating activities:
Undistributed loss of subsidiaries	24,823	14,802
Other, net	604	(246)
Net cash provided by operating activities	(2,089)	2,795
Cash flows from investing activities:
Payments for investments in and advances to subsidiaries	0	(20,000)
Repayment of investments in and advance to subsidiaries	0	203
Net cash provided by investing activities	0	(19,797)
Cash flows from financing activities:
Proceeds from exercise of stock options	643	266
Proceeds from issuance of common stock	0	57,834
Payment of dividends on preferred stock	(3,239)	(3,242)
Stock offering expenses	0	(683)
Payment of common dividends	(662)	(3,704)
Net cash used in financing activities	(3,258)	50,471
Net increase in cash and cash equivalents	(5,347)	33,469
Cash and cash equivalents, beginning of year	50,174	16,705
Cash and cash equivalents, end of year	$ 44,827	$ 50,174