Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] | Three months ended Three months ended September 30, 2017 September 30, 2016 Before Tax Income Tax Net Before Tax Income Tax Net Accumulated unrealized gains, net, on investments available for sale, beginning of period $ 53,214 $ 18,097 $ 35,117 $ 308,777 $ 104,988 $ 203,789 Other comprehensive income (loss) before reclassification 23,208 7,890 15,318 (8,644 ) (2,939 ) (5,705 ) Reclassification adjustment for realized investment gains, net, included in realized gains on investments, net (12,512 ) (4,254 ) (8,258 ) (61,301 ) (20,842 ) (40,459 ) Effect on other comprehensive income 10,696 3,636 7,060 (69,945 ) (23,781 ) (46,164 ) Accumulated unrealized income, net, on investments available for sale, end of period $ 63,910 $ 21,733 $ 42,177 $ 238,832 $ 81,207 $ 157,625 Accumulated unrealized losses, net, on interest rate swap, beginning of period $ (5,330 ) $ (1,812 ) $ (3,518 ) $ (64,525 ) $ (21,940 ) $ (42,585 ) Other comprehensive income before reclassification 1,320 449 871 9,339 3,176 6,163 Effect on other comprehensive losses 1,320 449 871 9,339 3,176 6,163 Accumulated unrealized losses, net, on interest rate swap, end of period $ (4,010 ) $ (1,363 ) $ (2,647 ) $ (55,186 ) $ (18,764 ) $ (36,422 ) Accumulated other comprehensive gain, beginning of period $ 47,884 $ 16,285 $ 31,599 $ 244,252 $ 83,048 $ 161,204 Change in unrealized gains (losses), net, on investments available for sale 10,696 3,636 7,060 (69,945 ) (23,781 ) (46,164 ) Change in unrealized gains, net, on interest rate swap 1,320 449 871 9,339 3,176 6,163 Effect on other comprehensive income (loss) 12,016 4,085 7,931 (60,606 ) (20,605 ) (40,001 ) Accumulated other comprehensive income, end of period $ 59,900 $ 20,370 $ 39,530 $ 183,646 $ 62,443 $ 121,203 Nine months ended Nine months ended September 30, 2017 September 30, 2016 Before Tax Income Tax Net Before Tax Income Tax Net Accumulated unrealized loss, net, on investments available for sale, beginning of period $ (13,376 ) $ (4,544 ) $ (8,832 ) $ (34,498 ) $ (11,725 ) $ (22,773 ) Other comprehensive income before reclassification 126,520 43,017 83,503 283,306 96,324 186,982 Reclassification adjustment for realized investment gains, net, included in realized gains on investments, net (49,234 ) (16,740 ) (32,494 ) (9,976 ) (3,392 ) (6,584 ) Effect on other comprehensive income 77,286 26,277 51,009 273,330 92,932 180,398 Accumulated unrealized gains, net, on investments available for sale, end of period $ 63,910 $ 21,733 $ 42,177 $ 238,832 $ 81,207 $ 157,625 Accumulated unrealized losses, net, on interest rate swap, beginning of period $ (6,697 ) $ (2,277 ) $ (4,420 ) $ (18,016 ) $ (6,126 ) $ (11,890 ) Other comprehensive income (loss) before reclassification 2,687 914 1,773 (37,170 ) (12,638 ) (24,532 ) Effect on other comprehensive income (loss) 2,687 914 1,773 (37,170 ) (12,638 ) (24,532 ) Accumulated unrealized losses, net, on interest rate swap, end of period $ (4,010 ) $ (1,363 ) $ (2,647 ) $ (55,186 ) $ (18,764 ) $ (36,422 ) Accumulated other comprehensive loss, beginning of period $ (20,073 ) $ (6,821 ) $ (13,252 ) $ (52,514 ) $ (17,851 ) $ (34,663 ) Change in unrealized gains, net, on investments available for sale 77,286 26,277 51,009 273,330 92,932 180,398 Change in unrealized gains (losses), net, on interest rate swap 2,687 914 1,773 (37,170 ) (12,638 ) (24,532 ) Effect on other comprehensive income 79,973 27,191 52,782 236,160 80,294 155,866 Accumulated other comprehensive income, end of period $ 59,900 $ 20,370 $ 39,530 $ 183,646 $ 62,443 $ 121,203 |