XML 78 R66.htm IDEA: XBRL DOCUMENT v3.8.0.1
Investments - Breakdown of Investments with Unrealized Losses (Detail) - USD ($)
$ in Thousands
Dec. 31, 2017
Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]    
Continuous Unrealized Loss Position for Less than 12 Months, Fair Value $ 39,093 $ 101,600
Continuous Unrealized Loss Position for Less than 12 Months, Unrealized Losses (902) (1,781)
Continuous Unrealized Loss Position for 12 Months or Greater, Fair Value 21,484 5,701
Continuous Unrealized Loss Position for 12 Months or Greater, Unrealized Losses (461) (351)
Total Fair Value 60,577 107,301
Total Unrealized Losses (1,363) (2,132)
Deferred Compensation Plan Assets [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Continuous Unrealized Loss Position for Less than 12 Months, Fair Value 1,922 294
Continuous Unrealized Loss Position for Less than 12 Months, Unrealized Losses (81) (12)
Continuous Unrealized Loss Position for 12 Months or Greater, Fair Value 262 245
Continuous Unrealized Loss Position for 12 Months or Greater, Unrealized Losses (15) (30)
Total Fair Value 2,184 539
Total Unrealized Losses (96) (42)
Corporate Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Continuous Unrealized Loss Position for Less than 12 Months, Fair Value 16,015 32,562
Continuous Unrealized Loss Position for Less than 12 Months, Unrealized Losses (58) (166)
Continuous Unrealized Loss Position for 12 Months or Greater, Fair Value 6,112 2,722
Continuous Unrealized Loss Position for 12 Months or Greater, Unrealized Losses (97) (8)
Total Fair Value 22,127 35,284
Total Unrealized Losses (155) (174)
Municipal Fixed-Rate Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Continuous Unrealized Loss Position for Less than 12 Months, Fair Value 230 8,936
Continuous Unrealized Loss Position for Less than 12 Months, Unrealized Losses   (37)
Continuous Unrealized Loss Position for 12 Months or Greater, Fair Value 1,165  
Continuous Unrealized Loss Position for 12 Months or Greater, Unrealized Losses (22)  
Total Fair Value 1,395 8,936
Total Unrealized Losses (22) (37)
Asset-Backed Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Continuous Unrealized Loss Position for Less than 12 Months, Fair Value 4,941 2,986
Continuous Unrealized Loss Position for Less than 12 Months, Unrealized Losses (17) (14)
Continuous Unrealized Loss Position for 12 Months or Greater, Fair Value 179  
Continuous Unrealized Loss Position for 12 Months or Greater, Unrealized Losses (3)  
Total Fair Value 5,120 2,986
Total Unrealized Losses (20) (14)
Mortgage/Agency-Backed Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Continuous Unrealized Loss Position for Less than 12 Months, Fair Value 3,062 7,842
Continuous Unrealized Loss Position for Less than 12 Months, Unrealized Losses (8) (81)
Continuous Unrealized Loss Position for 12 Months or Greater, Fair Value 1,673 1,239
Continuous Unrealized Loss Position for 12 Months or Greater, Unrealized Losses (38) (10)
Total Fair Value 4,735 9,081
Total Unrealized Losses (46) (91)
U.S. Government Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Continuous Unrealized Loss Position for Less than 12 Months, Fair Value 2,754 26,449
Continuous Unrealized Loss Position for Less than 12 Months, Unrealized Losses (26) (270)
Continuous Unrealized Loss Position for 12 Months or Greater, Fair Value 11,549  
Continuous Unrealized Loss Position for 12 Months or Greater, Unrealized Losses (148)  
Total Fair Value 14,303 26,449
Total Unrealized Losses (174) (270)
Marketable Equity Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Continuous Unrealized Loss Position for Less than 12 Months, Fair Value 10,169 21,607
Continuous Unrealized Loss Position for Less than 12 Months, Unrealized Losses (712) (1,200)
Continuous Unrealized Loss Position for 12 Months or Greater, Fair Value 544 1,495
Continuous Unrealized Loss Position for 12 Months or Greater, Unrealized Losses (138) (303)
Total Fair Value 10,713 23,102
Total Unrealized Losses $ (850) (1,503)
Foreign Government Bonds [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Continuous Unrealized Loss Position for Less than 12 Months, Fair Value   924
Continuous Unrealized Loss Position for Less than 12 Months, Unrealized Losses   (1)
Total Fair Value   924
Total Unrealized Losses   $ (1)