Fair Value Measurements (Summary of Changes in Fair Value of Level 3 Assets Measured on Recurring Basis) (Detail) - USD ($)
$ in Thousands |
3 Months Ended |
6 Months Ended |
Jun. 30, 2016 |
Jun. 30, 2015 |
Jun. 30, 2016 |
Jun. 30, 2015 |
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
| Fair value at beginning of period |
$ 16,325
|
$ 32,566
|
$ 50,139
|
$ 16,538
|
| Transfers into Level 3 |
2,948
|
2,504
|
857
|
2,504
|
| Transfers out of Level 3 |
(6,602)
|
(26,083)
|
(37,145)
|
(26,083)
|
| Included in earnings |
(36)
|
(43)
|
(146)
|
(1,056)
|
| Included in other comprehensive income (loss) |
234
|
(205)
|
658
|
(545)
|
| Purchases |
4,740
|
4,488
|
8,093
|
37,045
|
| Sales |
(1,446)
|
(481)
|
(4,522)
|
(15,587)
|
| Settlements |
(947)
|
(1,388)
|
(2,718)
|
(1,458)
|
| Fair value at end of period |
15,216
|
11,358
|
15,216
|
11,358
|
| Net realized investment gains (losses) |
8,070
|
3,868
|
13,176
|
2,915
|
| Level 3 |
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
| Net realized investment gains (losses) |
0
|
0
|
(5)
|
0
|
| U.S. Corporate Debt Securities |
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
| Fair value at beginning of period |
14,993
|
30,031
|
43,567
|
0
|
| Transfers into Level 3 |
2,948
|
1,030
|
857
|
1,030
|
| Transfers out of Level 3 |
(5,840)
|
(24,063)
|
(33,372)
|
(24,063)
|
| Included in earnings |
(36)
|
(43)
|
(111)
|
(41)
|
| Included in other comprehensive income (loss) |
179
|
(193)
|
667
|
37
|
| Purchases |
4,640
|
4,415
|
7,993
|
34,454
|
| Sales |
(1,446)
|
(481)
|
(3,473)
|
(653)
|
| Settlements |
(945)
|
(1,382)
|
(1,635)
|
(1,450)
|
| Fair value at end of period |
14,493
|
9,314
|
14,493
|
9,314
|
| U.S. Corporate Debt Securities | Level 3 |
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
| Net realized investment gains (losses) |
0
|
0
|
(5)
|
0
|
| Foreign Corporate Debt Securities |
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
| Fair value at beginning of period |
1,332
|
2,535
|
6,572
|
0
|
| Transfers into Level 3 |
0
|
1,474
|
0
|
1,474
|
| Transfers out of Level 3 |
(762)
|
(2,020)
|
(3,773)
|
(2,020)
|
| Included in earnings |
0
|
0
|
(35)
|
0
|
| Included in other comprehensive income (loss) |
55
|
(12)
|
(9)
|
7
|
| Purchases |
100
|
73
|
100
|
2,591
|
| Sales |
0
|
0
|
(1,049)
|
0
|
| Settlements |
(2)
|
(6)
|
(1,083)
|
(8)
|
| Fair value at end of period |
723
|
2,044
|
723
|
2,044
|
| Foreign Corporate Debt Securities | Level 3 |
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
| Net realized investment gains (losses) |
$ 0
|
0
|
$ 0
|
0
|
| Non-Agency Mortgage-Backed Securities |
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
| Fair value at beginning of period |
|
|
|
16,538
|
| Transfers into Level 3 |
|
|
|
0
|
| Transfers out of Level 3 |
|
|
|
0
|
| Included in earnings |
|
|
|
(1,015)
|
| Included in other comprehensive income (loss) |
|
|
|
(589)
|
| Purchases |
|
|
|
0
|
| Sales |
|
|
|
(14,934)
|
| Settlements |
|
|
|
0
|
| Fair value at end of period |
|
$ 0
|
|
0
|
| Non-Agency Mortgage-Backed Securities | Level 3 |
|
|
|
|
| Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |
|
|
|
|
| Net realized investment gains (losses) |
|
|
|
$ 0
|