Consolidated Statements of Changes in Stockholders' Equity (Parenthetical)  | 
3 Months Ended | 9 Months Ended | 
|---|---|---|
| 
 Sep. 30, 2018  
$ / shares  
shares 
 | 
 Sep. 30, 2018  
$ / shares  
shares 
 | 
|
| Stock Issued During Period, Shares, Acquisitions | shares | 161,875 | 161,875 | 
| Business Acquisition, Share Price | $ / shares | $ 42.80 | $ 42.80 | 
| X | ||||||||||
- Definition Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination. No definition available. 
  | 
| X | ||||||||||
- Definition Number of shares of stock issued during the period pursuant to acquisitions. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
  |