Quarterly report pursuant to Section 13 or 15(d)

Accumulated Other Comprehensive Income - Activity in Accumulated Other Comprehensive Income (Detail)

v3.5.0.2
Accumulated Other Comprehensive Income - Activity in Accumulated Other Comprehensive Income (Detail) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
Balance at beginning of period     $ 493,918 $ 453,387
OCI, before Reclassifications, Net of Tax, Attributable to Parent $ (1,520) $ 3,783 7,916 7,839
Reclassification from AOCI, Current Period, Net of Tax, Attributable to Parent 46 2,048 46 6,144
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent (1,566) 1,735 7,870 1,695
Balance at end of period 531,198 485,449 531,198 485,449
Accumulated Net Unrealized Investment Gain (Loss) [Member]        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
AOCI before Tax, Attributable to Parent 13,816 (1,079) (2,331) (985)
OCI, before Reclassifications, before Tax, Attributable to Parent (2,629) 5,064 13,518 9,066
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent 46 2,048 46 6,144
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent (2,675) 3,016 13,472 2,922
AOCI before Tax, Attributable to Parent 11,141 1,937 11,141 1,937
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Interest-Only Strip [Member]        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
AOCI before Tax, Attributable to Parent 0 16 9 16
OCI, before Reclassifications, before Tax, Attributable to Parent 0 (7) (9) (7)
Reclassification from AOCI, Current Period, before Tax, Attributable to Parent 0 0 0 0
Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent 0 (7) (9) (7)
AOCI before Tax, Attributable to Parent 0 9 0 9
AOCI Attributable to Parent [Member]        
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]        
AOCI Tax, Attributable to Parent (4,695) 1,486 2,007 1,432
Balance at beginning of period 9,121 423 (315) 463
Other comprehensive (loss) income before reclassification, tax 1,109 (1,274) (5,593) (1,220)
Reclassification from accumulated other comprehensive income, tax 0 0 0 0
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent (1,109) 1,274 5,593 1,220
AOCI Tax, Attributable to Parent (3,586) 212 (3,586) 212
Balance at end of period $ 7,555 $ 2,158 $ 7,555 $ 2,158