Summary of Significant Accounting Policies - Schedule of Accumulated Other Comprehensive Income, Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Jan. 01, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 752,557	$ 708,146
Cumulative effect from change in hedge accounting				$ 27
Adjusted Beginning Balance				708,644
Other comprehensive income/(loss) before reclassifications	(777)	23,240
Amounts reclassified from AOCI	(2,925)	(2,241)
Other comprehensive (loss)/income net of tax	(3,702)	20,999
Ending balance	763,298	745,266
Total [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	24,956	51,085
Adjusted Beginning Balance			$ 24,956	51,112
Other comprehensive (loss)/income net of tax	(3,702)	20,999
Ending balance	21,254	72,111
Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member] \| Available-for-sale Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(25,360)	(1,676)
Adjusted Beginning Balance			(25,360)	(1,676)
Other comprehensive income/(loss) before reclassifications	3,318	18,187
Amounts reclassified from AOCI	(758)	(1,417)
Other comprehensive (loss)/income net of tax	2,560	16,770
Ending balance	(22,800)	15,094
Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member] \| Held-to-maturity Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	43,443	48,236
Adjusted Beginning Balance			43,443	48,236
Other comprehensive income/(loss) before reclassifications	0	0
Amounts reclassified from AOCI	(1,787)	(1,035)
Other comprehensive (loss)/income net of tax	(1,787)	(1,035)
Ending balance	41,656	47,201
Cash Flow Hedge [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	6,873	4,525
Cumulative effect from change in hedge accounting				27
Adjusted Beginning Balance			$ 6,873	$ 4,552
Other comprehensive income/(loss) before reclassifications	(4,095)	5,053
Amounts reclassified from AOCI	(380)	211
Other comprehensive (loss)/income net of tax	(4,475)	5,264
Ending balance	$ 2,398	$ 9,816

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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

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

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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