CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Common Stock, Dividends, Per Share, Declared	$ 0.85	$ 0.73	$ 0.63
Stockholders' Equity Note, Stock Split		3-for-2

Description of the stock split arrangement. Also provide the retroactive effect given by a stock split that occurs after the balance date but before the release of financial statements.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Name:	us-gaap_StockholdersEquityNoteStockSplit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration