Annual report pursuant to Section 13 and 15(d)

Fair Value Measurements (Fair Value Measurements By Level For Assets Measured At Fair Value On A Recurring Basis) (Details)

v2.4.0.8
Fair Value Measurements (Fair Value Measurements By Level For Assets Measured At Fair Value On A Recurring Basis) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2013
Dec. 31, 2012
Cash and cash equivalents $ 974,304 $ 745,933
U.S. Treasury securities and obligations of U.S. government corporations and agencies 224,423 97,360
Corporate securities 296,086 295,111
Municipal securities, General obligation 54,422 86,571
Municipal securities, Pre-refunded 10,917 5,422
Municipal securities, Revenue 69,054 84,064
Municipal securities, Variable rate demand notes 28,575 23,385
Asset backed securities 139,050 74,637
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure 33,891 0
Total investments 856,418 666,550
Cash and cash equivalents 26,642 14,455
Certificates of deposit 5,891 5,890
U.S. Treasury securities and obligations of U.S. government corporations and agencies 14,413 13,941
Total restricted deposits 46,946 34,286
Interest rate swap contract 9,576 16,304
Total assets at fair value 1,887,244 1,463,073
Level I [Member]
   
Cash and cash equivalents 974,304 745,933
U.S. Treasury securities and obligations of U.S. government corporations and agencies 212,185 57,114
Corporate securities 0 0
Municipal securities, General obligation 0 0
Municipal securities, Pre-refunded 0 0
Municipal securities, Revenue 0 0
Municipal securities, Variable rate demand notes 0 0
Asset backed securities 0 0
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure 0 0
Total investments 212,185 57,114
Cash and cash equivalents 26,642 14,455
Certificates of deposit 5,891 5,890
U.S. Treasury securities and obligations of U.S. government corporations and agencies 14,413 13,941
Total restricted deposits 46,946 34,286
Interest rate swap contract 0 0
Total assets at fair value 1,233,435 837,333
Level II [Member]
   
Cash and cash equivalents 0 0
U.S. Treasury securities and obligations of U.S. government corporations and agencies 12,238 40,246
Corporate securities 296,086 295,111
Municipal securities, General obligation 54,422 86,571
Municipal securities, Pre-refunded 10,917 5,422
Municipal securities, Revenue 69,054 84,064
Municipal securities, Variable rate demand notes 28,575 23,385
Asset backed securities 139,050 74,637
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure 33,891 0
Total investments 644,233 609,436
Cash and cash equivalents 0 0
Certificates of deposit 0 0
U.S. Treasury securities and obligations of U.S. government corporations and agencies 0 0
Total restricted deposits 0 0
Interest rate swap contract 9,576 16,304
Total assets at fair value 653,809 625,740
Level III [Member]
   
Cash and cash equivalents 0 0
U.S. Treasury securities and obligations of U.S. government corporations and agencies 0 0
Corporate securities 0 0
Municipal securities, General obligation 0 0
Municipal securities, Pre-refunded 0 0
Municipal securities, Revenue 0 0
Municipal securities, Variable rate demand notes 0 0
Asset backed securities 0 0
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure 0 0
Total investments 0 0
Cash and cash equivalents 0 0
Certificates of deposit 0 0
U.S. Treasury securities and obligations of U.S. government corporations and agencies 0 0
Total restricted deposits 0 0
Interest rate swap contract 0 0
Total assets at fair value $ 0 $ 0