Quarterly report pursuant to Section 13 or 15(d)

Public Stock Offering (Details Textual)

v3.8.0.1
Public Stock Offering (Details Textual) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Feb. 06, 2018
Mar. 31, 2018
Apr. 01, 2017
Subsidiary Sale Of Stock [Line Items]      
Proceeds from stock issued   $ 240,163 $ 205
Common stock      
Subsidiary Sale Of Stock [Line Items]      
Sale of stock   4,400,000  
Common stock | Public Offering [Member]      
Subsidiary Sale Of Stock [Line Items]      
Sale of stock 4,400,000    
Shares price per share $ 57.50    
Proceeds from stock issued $ 239,793