Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 13,910	$ 2,989	$ 11,897	$ 13,589	$ 12,079
Other comprehensive income (loss), net of tax:
Unrealized gains (losses) on available for sale securities arising during the period	(11,026)				457
Change in minimum pension liability	80				54
Other comprehensive income (loss)	(10,946)				511
Comprehensive income	$ 2,964				$ 12,590