Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Tax benefits exercise stock options	$ 407	$ 1,056
Common Stock [Member]
Tax benefits exercise stock options	407	1,056
Additional Paid-in Capital [Member]
Tax benefits exercise stock options	$ 407	$ 1,056

Amount of deferred tax expense from write-off of the deferred tax asset related to deductible stock options at exercise.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 20
-Section 55
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=96864182&loc=d3e11283-113907

Name:	us-gaap_DeferredTaxExpenseFromStockOptionsExercised
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration