Condensed Consolidated Statements Of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Unrealized gain on investments, net of tax expense of $12 and $61 in 2018 and $12 and $35 in 2017	$ 12	$ 12	$ 61	$ 35
Unrealized gain (loss), net of tax expense (benefit) of $62 and $1,846 in 2018 and $(1,836) and $(5,035) in 2017	62	(1,836)	1,846	(5,035)
Reclassification adjustment for (gains) losses included in net income, net of tax (expense) benefit of $(153) and $476 in 2018 and $333 and $(348) in 2017	$ (153)	$ 333	$ 476	$ (348)