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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				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Before Tax
Unrealized holding (losses)/gains on available-for-sale-securities	$ (27,482)		$ 2,795		$ (23,282)	$ 25,817
Other comprehensive (loss)/income before tax	(43,161)		1,644		(47,847)	28,225
Provision (Benefit)
Unrealized holding (losses)/gains on available-for-sale-securities	(5,771)		586		(4,889)	5,421
Other comprehensive (loss)/income	(9,064)		345		(10,048)	5,927
After Tax
Unrealized holding (losses)/gains on available-for-sale-securities	(21,711)		2,209		(18,393)	20,396
Less reclassification adjustments included in	4,874		2,688		7,798	4,929
Other comprehensive (loss)/income net of tax	(34,097)	$ (3,702)	1,299	$ 20,999	(37,799)	22,298
Unrealized (losses)/gains on cash flow hedges	(29,223)		3,987		(30,001)	27,227
Cash Flow Hedge [Member]
Before Tax
Other comprehensive (loss)/income before tax	(9,972)		2,194		(15,637)	8,857
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(9,510)		2,251		(14,695)	8,647
Provision (Benefit)
Other comprehensive (loss)/income	(2,094)		461		(3,284)	1,860
Unrealized (losses)/gains on cash flow hedges	(1,998)		473		(3,087)	1,816
After Tax
Less reclassification adjustments included in	366		45		745	(166)
Other comprehensive (loss)/income net of tax	(7,878)		1,733		(12,353)	6,997
Unrealized (losses)/gains on cash flow hedges	(7,512)		1,778		(11,608)	6,831
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	(28,588)		996		(25,347)	22,224
Provision (Benefit)
Other comprehensive (loss)/income	(6,004)		208		(5,323)	4,666
After Tax
Less reclassification adjustments included in	873		1,421		1,631	2,838
Other comprehensive (loss)/income net of tax	(22,584)		788		(20,024)	17,558
Unrealized (losses)/gains on cash flow hedges	(21,711)		2,209		(18,393)	20,396
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	(4,601)		(1,546)		(6,863)	(2,856)
Provision (Benefit)
Other comprehensive (loss)/income	(966)		(324)		(1,441)	(599)
After Tax
Less reclassification adjustments included in	3,635		1,222		5,422	2,257
Other comprehensive (loss)/income net of tax	(3,635)		(1,222)		(5,422)	(2,257)
Unrealized (losses)/gains on cash flow hedges	0		0		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	(956)		(1,791)		(1,909)	(3,578)
Provision (Benefit)
Less reclassification adjustments included in	(201)		(376)		(401)	(752)
After Tax
Less reclassification adjustments included in	(755)		(1,415)		(1,508)	(2,826)
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	(4,601)		(1,546)		(6,863)	(2,856)
Provision (Benefit)
Less reclassification adjustments included in	(966)		(324)		(1,441)	(599)
After Tax
Less reclassification adjustments included in	(3,635)		(1,222)		(5,422)	(2,257)
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	(150)		(8)		(156)	(15)
Provision (Benefit)
Less reclassification adjustments included in	(32)		(2)		(33)	(3)
After Tax
Less reclassification adjustments included in	(118)		(6)		(123)	(12)
Net interest income [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member] \| Cash Flow Hedge [Member]
Before Tax
Less reclassification adjustments included in	(462)		(57)		(942)	210
Provision (Benefit)
Less reclassification adjustments included in	(96)		(12)		(197)	44
After Tax
Less reclassification adjustments included in	$ (366)		$ (45)		$ (745)	$ 166