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Summary of Significant Accounting Policies - Schedule of Reclassification out of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Before Tax
Unrealized holding (losses)/gains on available-for-sale-securities	$ (23,943)			$ (12,590)			$ (47,225)	$ 13,227
Other comprehensive (loss)/income before tax	(38,204)			(11,909)			(86,051)	16,316
Provision (Benefit)
Unrealized holding (losses)/gains on available-for-sale-securities	(5,028)			(2,643)			(9,917)	2,777
Other comprehensive (loss)/income	(8,023)			(2,500)			(18,071)	3,427
After Tax
Unrealized holding (losses)/gains on available-for-sale-securities	(18,915)			(9,947)			(37,308)	10,450
Less reclassification adjustments included in	6,195			2,124			13,993	7,054
Other comprehensive (loss)/income net of tax	(30,181)	$ (34,097)	$ (3,702)	(9,409)	$ 1,299	$ 20,999	(67,980)	12,889
Unrealized (losses)/gains on cash flow hedges	(23,986)			(7,285)			(53,987)	19,943
Cash Flow Hedge [Member]
Before Tax
Other comprehensive (loss)/income before tax	(6,736)			3,181			(22,373)	12,038
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(6,419)			3,370			(21,113)	12,017
Provision (Benefit)
Other comprehensive (loss)/income	(1,415)			668			(4,699)	2,528
Unrealized (losses)/gains on cash flow hedges	(1,348)			708			(4,434)	2,524
After Tax
Less reclassification adjustments included in	250			149			995	(17)
Other comprehensive (loss)/income net of tax	(5,321)			2,513			(17,674)	9,510
Unrealized (losses)/gains on cash flow hedges	(5,071)			2,662			(16,679)	9,493
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	(24,925)			(13,546)			(50,272)	8,678
Provision (Benefit)
Other comprehensive (loss)/income	(5,234)			(2,844)			(10,557)	1,822
After Tax
Less reclassification adjustments included in	776			755			2,407	3,594
Other comprehensive (loss)/income net of tax	(19,691)			(10,702)			(39,715)	6,856
Unrealized (losses)/gains on cash flow hedges	(18,915)			(9,947)			(37,308)	10,450
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	(6,543)			(1,544)			(13,406)	(4,400)
Provision (Benefit)
Other comprehensive (loss)/income	(1,374)			(324)			(2,815)	(923)
After Tax
Less reclassification adjustments included in	5,169			1,220			10,591	3,477
Other comprehensive (loss)/income net of tax	(5,169)			(1,220)			(10,591)	(3,477)
Unrealized (losses)/gains on cash flow hedges	0			0			0	0
Net Interest Income [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Cash Flow Hedge [Member]
Before Tax
Less reclassification adjustments included in	(317)			(189)
Provision (Benefit)
Less reclassification adjustments included in	(67)			(40)
After Tax
Less reclassification adjustments included in	(250)			(149)
Net 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	(961)			(946)			(2,870)	(4,523)
Provision (Benefit)
Less reclassification adjustments included in	(202)			(199)			(603)	(949)
After Tax
Less reclassification adjustments included in	(759)			(747)			(2,267)	(3,574)
Net 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	(6,543)			(1,544)			(13,406)	(4,400)
Provision (Benefit)
Less reclassification adjustments included in	(1,374)			(324)			(2,815)	(923)
After Tax
Less reclassification adjustments included in	(5,169)			(1,220)			(10,591)	(3,477)
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	(21)			(10)			(177)	(26)
Provision (Benefit)
Less reclassification adjustments included in	(4)			(2)			(37)	(6)
After Tax
Less reclassification adjustments included in	$ (17)			$ (8)			(140)	(20)
Interest Expense [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Cash Flow Hedge [Member]
Before Tax
Less reclassification adjustments included in							(1,260)	21
Provision (Benefit)
Less reclassification adjustments included in							(265)	4
After Tax
Less reclassification adjustments included in							$ (995)	$ 17