Income Taxes (Details) - Rollforward of Unrecognized Tax Benefits - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance		$ 1,408	$ 912	$ 279
Additions for tax positions relating to the current year		640	480	635
Additions for tax positions relating to prior years		0	37	0
Reductions for tax positions relating to prior years		(9)	(21)	(2)
Ending balance		2,039	1,408	912
Interest and penalties not included above:
Interest expense, net of tax effect, and penalties	[1]	49	20	4
Accrued interest and penalties, net of tax effect, at end of year	[1]	$ 73	$ 24	$ 4

[1] Included in income tax expense in the Consolidated Statements of Income.