Changes in Accumulated Other Comprehensive Income by Component - Reclassification Adjustments (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Tax (expense) benefit	$ 2,736	$ (1,467)
Net income	9,156	72
Realized Gains (Losses) on Sale of Available-for-sale Securities \| Amounts Reclassified from Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gains (losses) from the sale of available-for-sale securities	4	(89)
Tax (expense) benefit	1	(19)
Net income	$ 3	$ (70)

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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