Summary of Significant Accounting Policies - Schedule of Reclassification out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Before Tax
Unrealized holding gains on available-for-sale-securities	$ 4,200	$ 23,022
Other comprehensive (loss)/income before tax	(4,686)	26,581
Provision (Benefit)
Unrealized holding gains on available-for-sale-securities	882	4,835
Other comprehensive (loss)/income	(984)	5,582
After Tax
Unrealized holding gains on available-for-sale-securities	3,318	18,187
Less reclassification adjustments included in	2,925	2,241
Other comprehensive (loss)/income net of tax	(3,702)	20,999
Unrealized (losses)/gains on cash flow hedges	(777)	23,240
Cash Flow Hedge [Member]
Before Tax
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(5,184)	6,396
Other comprehensive (loss)/income before tax	(5,665)	6,663
Provision (Benefit)
Other comprehensive (loss)/income	(1,190)	1,399
Unrealized (losses)/gains on cash flow hedges	(1,089)	1,343
After Tax
Less reclassification adjustments included in	380	(211)
Other comprehensive (loss)/income net of tax	(4,475)	5,264
Unrealized (losses)/gains on cash flow hedges	(4,095)	5,053
Available-for-sale Securities [Member] \| Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member]
Before Tax
Other comprehensive (loss)/income before tax	3,241	21,228
Provision (Benefit)
Other comprehensive (loss)/income	681	4,458
After Tax
Less reclassification adjustments included in	758	1,417
Other comprehensive (loss)/income net of tax	2,560	16,770
Unrealized (losses)/gains on cash flow hedges	3,318	18,187
Held-to-maturity Securities [Member] \| Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member]
Before Tax
Other comprehensive (loss)/income before tax	(2,262)	(1,310)
Provision (Benefit)
Other comprehensive (loss)/income	(475)	(275)
After Tax
Less reclassification adjustments included in	1,787	1,035
Other comprehensive (loss)/income net of tax	(1,787)	(1,035)
Unrealized (losses)/gains on cash flow hedges	0	0
Interest Income [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Available-for-sale Securities [Member] \| Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member]
Before Tax
Less reclassification adjustments included in	(953)	(1,787)
Provision (Benefit)
Less reclassification adjustments included in	(200)	(375)
After Tax
Less reclassification adjustments included in	(753)	(1,412)
Interest Income [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Held-to-maturity Securities [Member] \| Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member]
Before Tax
Less reclassification adjustments included in	(2,262)	(1,310)
Provision (Benefit)
Less reclassification adjustments included in	(475)	(275)
After Tax
Less reclassification adjustments included in	(1,787)	(1,035)
Other Income [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Available-for-sale Securities [Member] \| Accumulated Net Investment Gain (Loss) Including Portion Attributable to Noncontrolling Interest [Member]
Before Tax
Less reclassification adjustments included in	(6)	(7)
Provision (Benefit)
Less reclassification adjustments included in	(1)	(2)
After Tax
Less reclassification adjustments included in	(5)	(5)
Net interest income [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Cash Flow Hedge [Member]
Before Tax
Less reclassification adjustments included in	(481)	267
Provision (Benefit)
Less reclassification adjustments included in	(101)	56
After Tax
Less reclassification adjustments included in	$ (380)	$ 211

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