Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 14,855	$ 13,783
Unrealized gain (loss) on securities:
Unrealized holding (loss) gain arising during period	(8,864)	1,620
Less: reclassification adjustment for net loss (gain) included in net income	0	(269)
Income tax benefit (expense) related to items of other comprehensive income	2,543	(560)
Other comprehensive (loss) income, net of tax	(6,321)	791
Comprehensive income	$ 8,534	$ 14,574

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount before tax, after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount of tax expense (benefit) allocated to other comprehensive income (loss).

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Amount before tax and reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

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