Quarterly report pursuant to Section 13 or 15(d)

Significant Accounting Policies (Narrative) (Details)

v3.8.0.1
Significant Accounting Policies (Narrative) (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Accounting Policies [Abstract]    
Stock Repurchased and Retired During Period, Shares 121,987  
Stock Repurchase Program, Remaining Authorized Repurchase Amount $ 174,700  
Stock Repurchased and Retired During Period, Value 17,300  
Debt and Capital Lease Obligations 45,000 $ 95,000
Stock Repurchase Program, Authorized Amount 250,000  
Long-term Debt, Fair Value $ 46,400 $ 97,100