XML 77 R58.htm IDEA: XBRL DOCUMENT v3.8.0.1
Fair Value Measurements - Schedule of Reconciliation of Debt Securities (Detail) - Debt Securities [Member] - Fair Value, Inputs, Level 3 [Member] - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]    
Beginning balance $ 12,220 $ 12,658
Accrued interest income   1,306
Gains or losses recorded for the period    
Recognized in net income (5,585) (2,727)
Recognized in other comprehensive income 9,415 983
Ending balance $ 16,050 $ 12,220