Annual report pursuant to Section 13 and 15(d)

Debt and Credit Arrangements (Textual) (Detail)

v3.6.0.2
Debt and Credit Arrangements (Textual) (Detail)
$ in Millions
12 Months Ended
Dec. 31, 2016
USD ($)
Revolving credit facility [Member] | Line of Credit [Member]  
Debt Instrument [Line Items]  
Revolving credit facility with Wells Fargo Bank $ 150.0
Available amount under credit facility 140.0
Credit Agreement [Member] | Citibank, National Association [Member]  
Debt Instrument [Line Items]  
Proceeds from Lines of Credit $ 16.0