Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(31))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(30))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_StockholdersEquity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

CAPITAL RATIOS AND SHAREHOLDERS' EQUITY - Components of AOCI (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total shareholders’ equity	$ 1,779,837	$ 1,577,005	$ 1,552,918	$ 1,516,241	$ 1,497,657	$ 1,496,264
Accumulated other comprehensive income/(loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total shareholders’ equity	11,301	(2,906)	(13,470)	(21,266)	(15,427)	4,161
Net unrealized holding gain (loss) on AFS securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other accumulated comprehensive income (loss), before tax	18,056		(15,267)
Income taxes related to items of accumulated other comprehensive income	(4,738)		3,814
Total shareholders’ equity	13,318	(889)	(11,453)	(19,021)	(13,182)	6,008
Net unrealized holding (loss) on pension plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other accumulated comprehensive income (loss), before tax	(2,753)		(2,753)
Income taxes related to items of accumulated other comprehensive income	736		736
Total shareholders’ equity	$ (2,017)	$ (2,017)	$ (2,017)	$ (2,245)	$ (2,245)	$ (1,847)