Schedule II - Condensed Financial Information of Registrant, Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 75,089	$ 81,747	$ 50,752	$ 24,544
Deferred income tax asset, net	7,176	2,492
Income taxes receivable	800
Other assets	3,601	2,659
Total assets	773,063	667,849
Liabilities:
Accounts payable and accrued expenses	7,090	6,519
Other liabilities	20	1,088
Total liabilities	509,077	429,660
Stockholders' Equity [Abstract]
Common stock	212	210
Additional paid-in capital	158,485	155,082
Retained earnings	106,545	73,502
Accumulated other comprehensive (loss) income	(1,256)	9,395
Stockholders' equity	263,986	238,189	210,214	113,451
Total liabilities and stockholders' equity	773,063	667,849
Parent Company [Member]
Assets
Cash and cash equivalents	10,016	1,502	$ 1,868	$ 1,744
Due from subsidiaries	1,001	665
Investment in subsidiaries	251,591	235,091
Deferred income tax asset, net	369	198
Income taxes receivable	787	805
Other assets	549	164
Total assets	264,313	238,425
Liabilities:
Accounts payable and accrued expenses	308	236
Other liabilities	19	0
Total liabilities	327	236
Stockholders' Equity [Abstract]
Common stock	212	210
Additional paid-in capital	158,485	155,082
Retained earnings	106,545	73,502
Accumulated other comprehensive (loss) income	(1,256)	9,395
Stockholders' equity	263,986	238,189
Total liabilities and stockholders' equity	$ 264,313	$ 238,425