Independent Bank (INDB) 10-Q 3 May 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	May 01, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	Independent Bank Corp
Entity Central Index Key	776,901
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding	27,512,328	27,524,228

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($)		Mar. 31, 2018	Dec. 31, 2017
Assets
Cash and due from banks		$ 102,623,000	$ 103,485,000
Interest-earning deposits with banks		62,925,000	109,631,000
Securities
Trading		1,601,000	1,324,000
Trading Securities, Equity		20,075,000	0
Available for sale		445,750,000	447,498,000
Held to maturity (fair value $517,555 and $494,194)		528,861,000	497,688,000
Total securities		996,287,000	946,510,000
Loans held for sale (at fair value)		3,937,000	4,768,000
Loans
Commercial and industrial		903,214,000	888,528,000
Commercial real estate		3,102,271,000	3,116,561,000
Commercial construction		400,934,000	401,797,000
Small business		133,666,000	132,370,000
Residential real estate		761,331,000	754,329,000
Home equity - first position		617,164,000	612,990,000
Home equity - subordinate positions		434,288,000	439,098,000
Other consumer		9,188,000	9,880,000
Total loans	[1]	6,362,056,000	6,355,553,000
Less: allowance for loan losses		(60,862,000)	(60,643,000)
Net loans		6,301,194,000	6,294,910,000
Federal Home Loan Bank stock		13,027,000	11,597,000
Bank premises and equipment, net		95,214,000	94,722,000
Goodwill		231,806,000	231,806,000
Other intangible assets		8,462,000	9,341,000
Cash surrender value of life insurance policies		152,568,000	151,528,000
Other real estate owned and other foreclosed assets		358,000	612,000
Other assets		122,009,000	123,119,000
Total assets		8,090,410,000	8,082,029,000
Deposits
Demand deposits		2,167,361,000	2,159,396,000
Savings and interest checking accounts		2,606,257,000	2,599,922,000
Money market		1,323,138,000	1,325,634,000
Time certificates of deposit of $100,000 and over		293,266,000	278,531,000
Other time certificates of deposits		361,489,000	365,770,000
Total deposits		6,751,511,000	6,729,253,000
Borrowings
Federal Home Loan Bank borrowings		53,257,000	53,264,000
Securities Sold under Agreements to Repurchase		137,914,000	162,679,000
Junior subordinated debentures (less unamortized debt issuance costs of $124 and $125)		73,075,000	73,073,000
Subordinated debentures (less unamortized debt issuance costs of $307 and $318)		34,693,000	34,682,000
Total borrowings		298,939,000	323,698,000
Other liabilities		83,901,000	85,269,000
Total liabilities		7,134,351,000	7,138,220,000
Commitments and contingencies		0
Stockholders' equity
Preferred stock, $.01 par value, authorized: 1,000,000 shares, outstanding: none		0
Common stock, $.01 par value, authorized: 75,000,000 shares, issued and outstanding: 27,512,328 shares at March 31, 2018 and 27,450,190 shares at December 31, 2017 (includes 169,904 and 177,191 shares of unvested participating restricted stock awards, respectively)		273,000	273,000
Value of shares held in rabbi trust at cost: 155,373 shares at March 31, 2018 and 164,438 shares at December 31, 2017		(4,591,000)	(4,590,000)
Deferred compensation and other retirement benefit obligations		4,591,000	4,590,000
Additional paid in capital		479,715,000	479,430,000
Retained earnings		484,266,000	465,937,000
Accumulated other comprehensive loss, net of tax		(8,195,000)	(1,831,000)
Total stockholders’ equity		956,059,000	943,809,000
Total liabilities and stockholders' equity		$ 8,090,410,000	$ 8,082,029,000
[1]	The amount of net deferred costs on originated loans included in the ending balance was $6.4 million and $6.1 million at March 31, 2018 and December 31, 2017, respectively. Net unamortized discounts on acquired loans not deemed to be purchased credit impaired ("PCI") included in the ending balance was $9.1 million and $9.4 million at March 31, 2018 and December 31, 2017, respectively.

Consolidated Balance Sheets (U3

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Time certificates of deposit least amount	$ 100,000	$ 100,000
Held to Maturity, Fair Value, Total	$ 517,555,000	$ 494,194,000
Preferred Stock, par value	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	1,000,000	1,000,000
Preferred Stock, shares outstanding	0	0
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	75,000,000	75,000,000
Common Stock, unvested restricted Stock awards	169,904	177,191
Shares Held in Rabbi Trust	155,373.53	164,438
Common Stock Outstanding
Common Stock, Shares, Outstanding	27,512,328	27,450,190
Junior Subordinated Debt [Member]
Unamortized Debt Issuance Expense	$ 124,000	$ 125,000
Subordinated Debt [Member]
Unamortized Debt Issuance Expense	$ 307,000	$ 318,000

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Interest income
Interest and fees on loans	$ 67,184	$ 58,793
Interest Income, Securities, Operating, Taxable	6,219	5,367
Nontaxable interest and dividends on securities	16	26
Interest on loans held for sale	19	14
Interest on federal funds sold and short-term investments	311	207
Total interest and dividend income	73,749	64,407
Interest expense
Interest on deposits	3,935	2,767
Interest on borrowings	1,343	1,440
Total interest expense	5,278	4,207
Net interest income	68,471	60,200
Provision for loan losses	500	600
Net interest income after provision for loan losses	67,971	59,600
Noninterest income
Deposit account fees	4,431	4,544
Interchange and ATM fees	4,173	3,922
Investment management	6,142	5,614
Mortgage banking income	870	957
Available-For-Sale- Securities - Equity - Gross Realized Gains	0	4
Increase in cash surrender value of life insurance policies	947	964
Loan level derivative income	447	606
Other noninterest income	2,853	2,301
Total noninterest income	19,863	18,912
Noninterest expenses
Salaries and employee benefits	31,100	28,324
Occupancy and equipment expenses	7,408	6,158
Data processing & facilities management	1,286	1,272
FDIC assessment	798	783
Advertising expense	1,123	1,294
Available-For-Sale Securities - Equity Gross Realized Losses	0	3
Business Combination, Acquisition Related Costs	0	484
Software Maintenance	972	930
Other noninterest expenses	10,764	9,525
Total noninterest expenses	53,451	48,773
Income before income taxes	34,383	29,739
Provision for income taxes	6,828	9,014
Net income	$ 27,555	$ 20,725
Basic earnings per share (in dollars per share)	$ 1	$ 0.77
Diluted earnings per share (in dollars per share)	$ 1	$ 0.76
Weighted average common shares (basic) (in shares)	27,486,573	27,029,640
Common shares equivalents (in shares)	67,381	81,283
Weighted average common shares (diluted) (in shares)	27,553,954	27,110,923
Retained Earnings [Member]
Noninterest expenses
Net income	$ 27,555	$ 20,725
Cash dividends declared per common share (in dollars per share)	$ 0.38	$ 0.32

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income		$ 27,555	$ 20,725
Other comprehensive income (loss), net of tax
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax		(5,468)	531
Net change in fair value of cash flow hedges		215	89
Net change in other comprehensive income for defined benefit postretirement plans	[1]	117	78
Total other comprehensive income (loss)		(5,136)	698
Total comprehensive income		$ 22,419	$ 21,423
[1]	The amortization of prior service costs is included in the computation of net periodic pension cost as disclosed in the Employee Benefit Plans footnote in the Company's Annual Report on Form 10-K for the year ended December 31, 2017, filed with the Securities and Exchange Commission.

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands		Total	Common Stock Outstanding	Common Stock	Value of Shares Held in Rabbi Trust at Cost	Deferred Compensation and Other Retirement Benefit Obligations	Additional Paid in Capital	Retained Earnings		Accumulated Other Comprehensive Loss
Cash dividends declared per common share (in dollars per share)								$ 0.32
Balance March 31, 2018 at Dec. 31, 2016			27,005,813
Balance March 31, 2017 at Dec. 31, 2016		$ 864,690		$ 268	$ (4,277)	$ 4,277	$ 451,664	$ 414,095		$ (1,337)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		20,725						20,725
Other comprehensive loss		698								698
Common dividend declared ($0.32 and $0.29 per share for 2017 and 2016, respectively)		(8,653)						(8,653)
Proceeds from exercise of stock options, net of cash paid			7,688
Proceeds from exercise of stock options, net of cash paid		143		0			143
Stock based compensation		643					643
Restricted stock awards issued, net of awards surrendered			27,534
Restricted stock awards issued, net of awards surrendered		(1,336)		1			(1,337)
Shares issued under direct stock purchase plan			5,733
Shares issued under direct stock purchase plan		393					393
Deferred compensation and other retirement benefit obligations					(53)	53
Increase (Decrease) in Deferred Compensation		0
Balance December 31, 2017 at Mar. 31, 2017		877,480		269	(4,330)	4,330	452,048	$ 425,802		(639)
Balance December 31, 2016 at Mar. 31, 2017			27,046,768
Cash dividends declared per common share (in dollars per share)								$ 0
Balance March 31, 2018 at Dec. 31, 2016			27,005,813
Balance March 31, 2017 at Dec. 31, 2016		864,690		268	(4,277)	4,277	451,664	$ 414,095		(1,337)
Balance December 31, 2017 at Dec. 31, 2017		943,809		273	(4,590)	4,590	479,430	465,937		(1,831)
Balance December 31, 2016 at Dec. 31, 2017			27,450,190
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	[1]	177					542	$ (365)
Cash dividends declared per common share (in dollars per share)								$ 0.38
Prior Period Reclassification Adjustment		0						$ 397	[2]	(397)	[2]
Net income		27,555						27,555
Other comprehensive loss		(5,136)								(5,136)
Common dividend declared ($0.32 and $0.29 per share for 2017 and 2016, respectively)		(10,454)						(10,454)
Proceeds from exercise of stock options, net of cash paid			19,256
Proceeds from exercise of stock options, net of cash paid		143					143
Stock based compensation		1,041					1,041
Restricted stock awards issued, net of awards surrendered			36,961
Restricted stock awards issued, net of awards surrendered		(1,318)					(1,318)
Shares issued under direct stock purchase plan			5,921
Shares issued under direct stock purchase plan		419					419
Deferred compensation and other retirement benefit obligations					(1)	1
Balance December 31, 2017 at Mar. 31, 2018		956,059		$ 273	$ (4,591)	$ 4,591	$ 479,715	484,266		(8,195)
Balance December 31, 2016 at Mar. 31, 2018			27,512,328
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		$ 0						$ 831	[3]	$ (831)	[3]
[1]	Represents adjustment needed to reflect the cumulative impact on retained earnings for previously recognized stock based compensation, which included an adjustment for estimated forfeitures. Pursuant to the Company's adoption of Accounting Standards Update 2016-09, the Company has elected to recognize stock based compensation without inclusion of a forfeiture estimate, and as such has recognized this adjustment to present retained earnings consistent with this election.
[2]	Represents adjustment needed to reflect the cumulative impact on retained earnings for reclassification of the income tax effects attributable to accumulated other comprehensive income, as a result of the Tax Cuts and Jobs Act (the "Tax Act"). Pursuant to the Company's adoption of Accounting Standards Update 2018-02, the Company has elected to reclassify amounts stranded in other comprehensive income to retained earnings.
[3]	Represents adjustment needed to reflect the cumulative impact on retained earnings for the classification and measurement of investments in equity securities. Pursuant to the Company's adoption of Accounting Standards Update 2016-01, the Company's investments in equity securities will no longer be classified as available for sale, therefore the Company was required to reclassify the net unrealized gain recognized on the change in fair value of these equity securities from other comprehensive income to retained earnings.

Consolidated Statements of Sto7

Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Retained Earnings
Cash dividends declared per common share (in dollars per share)	$ 0.38	$ 0.32	$ 0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Income	$ 27,555,000	$ 20,725,000
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	4,181,000	3,557,000
Provision for loan losses	500,000	600,000
Deferred income tax expense	359,000	709,000
Unrealized Gain (Loss) on Investments	485,000
Net gain on sale of securities		(1,000)
Net (gain) loss on bank premises and equipment	(7,000)	4,000
Net (gain) loss on other real estate owned and foreclosed assets	1,000	(29,000)
Realized gain on sale leaseback transaction	(258,000)	(258,000)
Stock based compensation	1,041,000	643,000
Increase in cash surrender value of life insurance policies	(947,000)	(964,000)
Net change in:
Trading assets	(277,000)	(485,000)
Loans held for sale	805,000	2,594,000
Change in Fair Value on Loans Held for Sale	26,000	147,000
Other assets	2,594,000	18,384,000
Increase (Decrease) in Other Operating Liabilities	(2,175,000)	(8,192,000)
Total adjustments	6,328,000	16,709,000
Net cash provided by operating activities	33,883,000	37,434,000
Payments to Acquire Trading Securities Held-for-investment	(78,000)
Payments to Acquire Available-for-sale Securities, Equity		0
Cash flows used in investing activities
Proceeds from sales of securities available for sale		16,000
Proceeds from maturities and principal repayments of securities available for sale	11,040,000	12,107,000
Purchases of securities available for sale	(37,201,000)	(49,617,000)
Proceeds from maturities and principal repayments of securities held to maturity	22,888,000	19,101,000
Purchases of securities held to maturity	(53,995,000)	(34,090,000)
Net purchases of Federal Home Loan Bank stock	(1,430,000)	0
Investments in low income housing projects	(1,213,000)	(3,437,000)
Purchases of life insurance policies	(93,000)	(93,000)
Net increase in loans	(6,856,000)	(64,997,000)
Purchases of bank premises and equipment	(2,803,000)	(5,457,000)
Proceeds from the sale of bank premises and equipment	52,000	27,000
Proceeds from the sale of other real estate owned and foreclosed assets	253,000	1,255,000
Net cash used in investing activities	(69,436,000)	(125,185,000)
Cash flows provided by financing activities
Net increase (decrease) in time deposits	10,486,000	(33,219,000)
Net increase in other deposits	11,804,000	91,721,000
Net decrease in customer repurchase agreements	(24,765,000)	(31,141,000)
Net proceeds from exercise of stock options	143,000	143,000
Restricted stock awards issued, net of awards surrendered	(1,318,000)	(1,336,000)
Proceeds from shares issued under direct stock purchase plan	419,000	393,000
Common dividends paid	(8,784,000)	(7,832,000)
Net cash provided by (used in) financing activities	(12,015,000)	18,729,000
Net decrease in cash and cash equivalents	(47,568,000)	(69,022,000)
Cash and cash equivalents at beginning of year	213,116,000	289,095,000
Cash and cash equivalents at end of period	165,548,000	220,073,000
Supplemental schedule of noncash investing and financing activities
Real Estate Owned, Transfer from Real Estate Owned		457,000
Net increase in capital commitments relating to low income housing project investments	$ 9,000	$ 60,000

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BASIS OF PRESENTATION	BASIS OF PRESENTATION Independent Bank Corp. (the “Company”) is a state chartered, federally registered bank holding company, incorporated in 1985. The Company is the sole stockholder of Rockland Trust Company (“Rockland Trust” or the “Bank”), a Massachusetts trust company chartered in 1907. All material intercompany balances and transactions have been eliminated in consolidation. Certain previously reported amounts have been reclassified to conform to the current year’s presentation. The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all adjustments considered necessary for a fair presentation of the financial statements, primarily consisting of normal recurring adjustments, have been included. Results for the quarter ended March 31, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 or any other interim period. For further information, refer to the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 , filed with the Securities and Exchange Commission.

Recent Accounting Standards

Recent Accounting Standards	3 Months Ended
	Mar. 31, 2018
Recent Accounting Standards [Abstract]
RECENT ACCOUNTING STANDARDS	RECENT ACCOUNTING STANDARDS UPDATES Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") Topic 326 "Financial Instruments - Credit Losses" Update No. 2016-13. Update No. 2016-13 was issued in June 2016 to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. To achieve this objective, the amendments in this update replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The amendments affect entities holding financial assets and net investment in leases that are not accounted for at fair value through net income. The amendments affect loans, debt securities, trade receivables, net investments in leases, off-balance sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope that have the contractual right to receive cash. For public companies, the amendments in this update are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted as of fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company is currently assessing the impact of the adoption of this standard on the Company's consolidated financial position. FASB ASC Topic 842 "Leases" Update No. 2016-02. Update No. 2016-02 was issued in February 2016 and affects any entity that enters into a lease (as that term is defined in this update), with some specified scope exemptions. The core principle of this update is that a lessee should recognize in the statement of financial position a liability to make lease payments and a right-of-use asset representing its right to use the underlying asset for the lease term. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. The recognition, measurement, and presentation of expenses and cash flows arising from a lease have not significantly changed from previous GAAP. In addition, the accounting applied by a lessor is largely unchanged from that applied under previous GAAP. For public companies, the amendments in this update are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. The Company is currently in the process of reviewing its current lease agreements to assess the impact of the adoption of this standard. FASB ASC Topic 825-10 "Financial Instruments - Overall Recognition and Measurement of Financial Assets and Financial Liabilities" Update No. 2016-01. Update No. 2016-01 was issued in January 2016 to amend the guidance in U.S. GAAP on the classification and measurement of financial instruments. Although the update retains many current requirements, it significantly revises an entity's accounting related to (1) the classification and measurement of investments in equity securities and (2) the presentation of certain fair value changes for financial liabilities measured at fair value. The update also amends certain disclosure requirements associated with the fair value of financial instruments and various other aspects of recognition, measurement, presentation and disclosure of financial instruments. For public companies, the amendments in this update are effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Upon adoption of this standard on January 1, 2018, there was no material impact on the Company's consolidated financial position.

Securities

Securities	3 Months Ended
	Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
SECURITIES	SECURITIES Trading Securities The Company had trading securities of $1.6 million and $1.3 million as of March 31, 2018 and December 31, 2017 , respectively. These securities are held in a rabbi trust and will be used for future payments associated with the Company’s nonqualified 401(k) Restoration Plan and Nonqualified Deferred Compensation Plan. Equity Securities The Company had equity securities of $20.1 million as of March 31, 2018 . These securities consist primarily of mutual funds held in a rabbi trust and will be used for future payments associated with the Company’s supplemental executive retirement plans. These securities were previously classified as available for sale and were reclassified as equity securities due to a change in accounting guidance effective January 1, 2018. The equity securities were $20.6 million as of December 31, 2017 and are reflected accordingly as available for sale in the table below. Available for Sale and Held to Maturity Securities The following table presents a summary of the amortized cost, gross unrealized gains and losses and fair value of securities available for sale and securities held to maturity for the periods indicated: March 31, 2018 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available for sale securities U.S. government agency securities $ 35,478 $ — $ (535 ) $ 34,943 $ 35,475 $ 86 $ (131 ) $ 35,430 Agency mortgage-backed securities 226,111 1,266 (4,166 ) 223,211 214,934 1,897 (1,067 ) 215,764 Agency collateralized mortgage obligations 139,433 73 (4,314 ) 135,192 124,098 78 (2,164 ) 122,012 State, county, and municipal securities 2,232 22 — 2,254 2,237 37 — 2,274 Single issuer trust preferred securities issued by banks 2,002 3 — 2,005 2,012 4 — 2,016 Pooled trust preferred securities issued by banks and insurers 2,173 — (518 ) 1,655 2,179 — (539 ) 1,640 Small business administration pooled securities 47,434 — (944 ) 46,490 47,852 44 (118 ) 47,778 Equity securities — — — — 19,432 1,594 (442 ) 20,584 Total available for sale securities $ 454,863 $ 1,364 $ (10,477 ) $ 445,750 $ 448,219 $ 3,740 $ (4,461 ) $ 447,498 Held to maturity securities U.S. Treasury securities $ 1,005 $ 16 $ — $ 1,021 $ 1,006 $ 29 $ — $ 1,035 Agency mortgage-backed securities 192,961 474 (3,026 ) 190,409 204,768 1,791 (736 ) 205,823 Agency collateralized mortgage obligations 306,395 126 (8,703 ) 297,818 262,998 397 (4,987 ) 258,408 Single issuer trust preferred securities issued by banks 1,500 21 — 1,521 1,500 29 — 1,529 Small business administration pooled securities 27,000 95 (309 ) 26,786 27,416 183 (200 ) 27,399 Total held to maturity securities $ 528,861 $ 732 $ (12,038 ) $ 517,555 $ 497,688 $ 2,429 $ (5,923 ) $ 494,194 Total $ 983,724 $ 2,096 $ (22,515 ) $ 963,305 $ 945,907 $ 6,169 $ (10,384 ) $ 941,692 When securities are sold, the adjusted cost of the specific security sold is used to compute the gain or loss on the sale. The actual maturities of certain securities may differ from the contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. A schedule of the contractual maturities of securities available for sale and securities held to maturity as of March 31, 2018 is presented below: Due in one year or less Due after one year to five years Due after five to ten years Due after ten years Total Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value (Dollars in thousands) Available for sale securities U.S. government agency securities $ 2,997 $ 2,995 $ 20,016 $ 19,860 $ 12,465 $ 12,088 $ — $ — $ 35,478 $ 34,943 Agency mortgage-backed securities 84 85 43,016 42,235 97,629 96,201 85,382 84,690 226,111 223,211 Agency collateralized mortgage obligations 8 8 — — — — 139,425 135,184 139,433 135,192 State, county, and municipal securities — — 1,026 1,028 1,206 1,226 — — 2,232 2,254 Single issuer trust preferred securities issued by banks — — — — — — 2,002 2,005 2,002 2,005 Pooled trust preferred securities issued by banks and insurers — — — — — — 2,173 1,655 2,173 1,655 Small business administration pooled securities — — — — — — 47,434 46,490 47,434 46,490 Total available for sale securities $ 3,089 $ 3,088 $ 64,058 $ 63,123 $ 111,300 $ 109,515 $ 276,416 $ 270,024 $ 454,863 $ 445,750 Held to maturity securities U.S. Treasury securities $ — $ — $ 1,005 $ 1,021 $ — $ — $ — $ — $ 1,005 $ 1,021 Agency mortgage-backed securities — — 9,052 8,932 14,057 14,146 169,852 167,331 192,961 190,409 Agency collateralized mortgage obligations — — — — 1,426 1,423 304,969 296,395 306,395 297,818 Single issuer trust preferred securities issued by banks — — — — — — 1,500 1,521 1,500 1,521 Small business administration pooled securities — — — — — — 27,000 26,786 27,000 26,786 Total held to maturity securities $ — $ — $ 10,057 $ 9,953 $ 15,483 $ 15,569 $ 503,321 $ 492,033 $ 528,861 $ 517,555 Inclusive in the table above is $7.4 million of callable securities at March 31, 2018 . The carrying value of securities pledged to secure public funds, trust deposits, repurchase agreements and for other purposes, as required or permitted by law, was $552.7 million and $547.2 million at March 31, 2018 and December 31, 2017 , respectively. At March 31, 2018 and December 31, 2017 , the Company had no investments in obligations of individual states, counties, or municipalities which exceeded 10% of stockholders’ equity . Other-Than-Temporary Impairment ("OTTI") The Company continually reviews investment securities for the existence of OTTI, taking into consideration current market conditions, the extent and nature of changes in fair value, issuer rating changes and trends, the credit worthiness of the obligor of the security, volatility of earnings, current analysts’ evaluations, the Company’s intent to sell the security, whether it is more likely than not that the Company will be required to sell the debt security before its anticipated recovery, as well as other qualitative factors. The term “other-than-temporary” is not intended to indicate that the decline is permanent, but indicates that the prospects for a near-term recovery of value is not necessarily favorable, or that there is a lack of evidence to support a realizable value equal to or greater than the carrying value of the investment. The following tables show the gross unrealized losses and fair value of the Company’s investments in an unrealized loss position, which the Company has not deemed to be OTTI, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position: March 31, 2018 Less than 12 months 12 months or longer Total # of holdings Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (Dollars in thousands) U.S. government agency securities 6 $ 34,943 $ (535 ) $ — $ — $ 34,943 $ (535 ) Agency mortgage-backed securities 140 338,326 (6,624 ) 14,205 (568 ) 352,531 (7,192 ) Agency collateralized mortgage obligations 51 244,572 (5,384 ) 150,834 (7,633 ) 395,406 (13,017 ) Pooled trust preferred securities issued by banks and insurers 1 — — 1,655 (518 ) 1,655 (518 ) Small business administration pooled securities 6 56,839 (1,074 ) 9,569 (179 ) 66,408 (1,253 ) Total temporarily impaired securities 204 $ 674,680 $ (13,617 ) $ 176,263 $ (8,898 ) $ 850,943 $ (22,515 ) December 31, 2017 Less than 12 months 12 months or longer Total # of holdings Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (Dollars in thousands) U.S.government agency securities 4 $ 24,343 $ (131 ) $ — $ — $ 24,343 $ (131 ) Agency mortgage-backed securities 84 235,411 (1,493 ) 14,886 (310 ) 250,297 (1,803 ) Agency collateralized mortgage obligations 42 178,142 (1,579 ) 159,506 (5,572 ) 337,648 (7,151 ) Pooled trust preferred securities issued by banks and insurers 1 — — 1,640 (539 ) 1,640 (539 ) Small business administration pooled securities 4 34,553 (223 ) 9,647 (95 ) 44,200 (318 ) Equity securities 28 3,290 (39 ) 7,619 (403 ) 10,909 (442 ) Total temporarily impaired securities 163 $ 475,739 $ (3,465 ) $ 193,298 $ (6,919 ) $ 669,037 $ (10,384 ) The Company does not intend to sell these investments and has determined, based upon available evidence, that it is more likely than not that the Company will not be required to sell each security before the recovery of its amortized cost basis. As a result, the Company does not consider these investments to be OTTI and accordingly, there was no OTTI recorded and no cumulative credit related component of OTTI for the three months ended March 31, 2018 and 2017 . The Company made this determination by reviewing various qualitative and quantitative factors regarding each investment category, such as current market conditions, extent and nature of changes in fair value, issuer rating changes and trends, volatility of earnings, and current analysts’ evaluations. As a result of the Company’s review of these qualitative and quantitative factors, the causes of the impairments listed in the table above by category are as follows at March 31, 2018 : • U.S. Government Agency Securities, Agency Mortgage-Backed Securities, Agency Collateralized Mortgage Obligations and Small Business Administration Pooled Securities: These portfolios have contractual terms that generally do not permit the issuer to settle the securities at a price less than the current par value of the investment. The decline in market value of these securities is attributable to changes in interest rates and not credit quality. Additionally, these securities are implicitly guaranteed by the U.S. Government or one of its agencies. • Pooled Trust Preferred Securities: This portfolio consists of one below investment grade security which is performing. The unrealized loss on this security is attributable to the illiquid nature of the trust preferred market in the current economic and regulatory environment. Management evaluates collateral credit and instrument structure, including current and expected deferral and default rates and timing. In addition, discount rates are determined by evaluating comparable spreads observed currently in the market for similar instruments.

Loans, Allowance for Loan Losse

Loans, Allowance for Loan Losses and Credit Quality	3 Months Ended
	Mar. 31, 2018
Loans, Allowance for Loan Losses and Credit Quality [Abstract]
LOANS, ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY	90 Days and Accruing Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Current (Dollars in thousands) Loan Portfolio Commercial and industrial 4 $ 411 2 $ 101 14 $ 30,638 20 $ 31,150 $ 872,064 $ 903,214 $ — Commercial real estate 9 3,127 4 1,253 6 1,413 19 5,793 3,096,478 3,102,271 — Commercial construction 2 855 — — — — 2 855 400,079 400,934 — Small business 11 107 8 69 23 347 42 523 133,143 133,666 — Residential real estate 13 1,834 7 1,100 19 3,052 39 5,986 755,345 761,331 — Home equity 22 2,266 8 882 26 2,440 56 5,588 1,045,864 1,051,452 — Other consumer (1) 221 104 7 2 18 20 246 126 9,062 9,188 9 Total 282 $ 8,704 36 $ 3,407 106 $ 37,910 424 $ 50,021 $ 6,312,035 $ 6,362,056 $ 9 December 31, 2017 30-59 days 60-89 days 90 days or more Total Past Due Total Financing Receivables Recorded Investment >90 Days and Accruing Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Current (Dollars in thousands) Loan Portfolio Commercial and industrial 2 $ 195 2 $ 370 14 $ 32,007 18 $ 32,572 $ 855,956 $ 888,528 $ — Commercial real estate 7 3,060 — — 9 1,793 16 4,853 3,111,708 3,116,561 — Commercial construction — — — — — — — — 401,797 401,797 — Small business 17 339 11 144 10 57 38 540 131,830 132,370 — Residential real estate 6 870 13 2,385 22 3,471 41 6,726 747,603 754,329 — Home equity 22 1,310 6 451 20 2,025 48 3,786 1,048,302 1,052,088 — Other consumer (1) 265 197 16 27 17 45 298 269 9,611 9,880 8 Total 319 $ 5,971 48 $ 3,377 92 $ 39,398 459 $ 48,746 $ 6,306,807 $ 6,355,553 $ 8 (1) Other consumer portfolio is inclusive of deposit account overdrafts recorded as loan balances. Troubled Debt Restructurings In the course of resolving nonperforming loans, the Bank may choose to restructure the contractual terms of certain loans. The Bank attempts to work out an alternative payment schedule with the borrower in order to avoid foreclosure actions. Any loans that are modified are reviewed by the Bank to identify if a TDR has occurred, which is when, for economic or legal reasons related to a borrower’s financial difficulties, the Bank grants a concession to the borrower that it would not otherwise consider. Terms may be modified to fit the ability of the borrower to repay in line with its current financial status and the restructuring of the loan may include the transfer of assets from the borrower to satisfy the debt, a modification of loan terms, or a combination of the two. The following table shows the Company’s total TDRs and other pertinent information as of the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) TDRs on accrual status $ 25,617 $ 25,852 TDRs on nonaccrual 5,637 6,067 Total TDRs $ 31,254 $ 31,919 Amount of specific reserves included in the allowance for loan losses associated with TDRs $ 1,257 $ 1,342 Additional commitments to lend to a borrower who has been a party to a TDR $ 600 $ 487 The Company’s policy is to have any restructured loan which is on nonaccrual status prior to being modified remain on nonaccrual status for six months subsequent to being modified before management considers its return to accrual status. If the restructured loan is on accrual status prior to being modified, it is reviewed to determine if the modified loan should remain on accrual status. Additionally, loans classified as TDRs are adjusted to reflect the changes in value of the recorded investment in the loan, if any, resulting from the granting of a concession. For all residential loan modifications, the borrower must perform during a 90 day trial period before the modification is finalized. The following tables show the modifications which occurred during the periods indicated and the change in the recorded investment subsequent to the modifications occurring: Three Months Ended March 31, 2018 Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment (1) (Dollars in thousands) Troubled debt restructurings Commercial real estate 1 445 445 Home equity 2 242 242 Total 3 $ 687 $ 687 Three Months Ended March 31, 2017 Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment (1) (Dollars in thousands) Troubled debt restructurings Commercial and industrial 2 $ 80 $ 80 Commercial real estate 4 934 934 Small business 4 143 143 Home equity 2 140 140 Total 12 $ 1,297 $ 1,297 (1) The post-modification balances represent the legal principal balance of the loan on the date of modification. These amounts may show an increase when modifications include a capitalization of interest. The following table shows the Company’s post-modification balance of TDRs listed by type of modification during the periods indicated: Three Months Ended March 31 2018 2017 (Dollars in thousands) Extended maturity $ 445 $ 1,207 Court ordered concession 242 90 Total $ 687 $ 1,297 The Company considers a loan to have defaulted when it reaches 90 days past due. There were no loans modified during the preceding twelve months that had subsequently defaulted during the three months ended March 31, 2018 and 2017 . All TDR loans are considered impaired and therefore are subject to a specific review for impairment. The impairment analysis appropriately discounts the present value of the anticipated cash flows by the loan’s contractual rate of interest in effect prior to the loan’s modification. The amount of impairment, if any, is recorded as a specific loss allocation to each individual loan in the allowance for loan losses. Commercial loans (commercial and industrial, commercial construction, commercial real estate and small business loans), residential loans, and home equity loans that have been classified as TDRs and which subsequently default are reviewed to determine if the loan should be deemed collateral dependent. In such an instance, any shortfall between the value of the collateral and the carrying value of the loan is determined by measuring the recorded investment in the loan against the fair value of the collateral less costs to sell. The Company charges off the amount of any confirmed loan loss in the period when the loans, or portion of loans, are deemed uncollectible. Smaller balance consumer TDR loans are reviewed for performance to determine when a charge-off is appropriate. Impaired Loans A loan is considered impaired when, based on current information and events, it is probable that the Company will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. The tables below set forth information regarding the Company’s impaired loans by loan portfolio at the dates indicated: March 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 32,878 $ 38,785 $ — Commercial real estate 14,747 15,894 — Small business 727 797 — Residential real estate 4,234 4,367 — Home equity 5,248 5,357 — Other consumer 85 86 — Subtotal 57,919 65,286 — With an allowance recorded Commercial and industrial $ 226 $ 226 $ 9 Commercial real estate 1,723 1,723 37 Small business 126 132 3 Residential real estate 9,044 9,790 944 Home equity 1,678 1,919 248 Other consumer 207 209 16 Subtotal 13,004 13,999 1,257 Total $ 70,923 $ 79,285 $ 1,257 December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 34,267 $ 38,329 $ — Commercial real estate 13,245 14,374 — Small business 556 619 — Residential real estate 4,264 4,397 — Home equity 4,950 5,056 — Other consumer 91 92 — Subtotal 57,373 62,867 — With an allowance recorded Commercial and industrial $ 376 $ 376 $ 10 Commercial real estate 3,393 3,399 42 Small business 147 153 1 Residential real estate 9,420 10,154 1,007 Home equity 1,876 2,110 265 Other consumer 216 217 17 Subtotal 15,428 16,409 1,342 Total $ 72,801 $ 79,276 $ 1,342 The following tables set forth information regarding interest income recognized on impaired loans, by portfolio, for the periods indicated: Three Months Ended March 31, 2018 Average Recorded Investment Interest Income Recognized (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 33,784 $ 31 Commercial real estate 14,855 157 Small business 710 5 Residential real estate 4,254 53 Home equity 5,280 53 Other consumer 87 1 Subtotal 58,970 300 With an allowance recorded Commercial and industrial $ 227 $ 2 Commercial real estate 1,730 24 Small business 131 2 Residential real estate 9,060 71 Home equity 1,688 12 Other consumer 211 2 Subtotal 13,047 113 Total $ 72,017 $ 413 Three Months Ended March 31, 2017 Average Recorded Investment Interest Income Recognized (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 39,193 $ 208 Commercial real estate 9,678 91 Small business 304 3 Residential real estate 3,671 43 Home equity 4,323 44 Other consumer 120 2 Subtotal 57,289 391 With an allowance recorded Commercial and industrial $ 10,178 $ 4 Commercial real estate 5,189 50 Small business 457 5 Residential real estate 10,057 85 Home equity 1,402 13 Other consumer 245 2 Subtotal 27,528 159 Total $ 84,817 $ 550 Purchased Credit Impaired Loans Certain loans acquired by the Company may have shown evidence of deterioration of credit quality since origination and it was therefore deemed unlikely that the Company would be able to collect all contractually required payments. As such, these loans were deemed to be PCI loans and the carrying value and prospective income recognition are predicated upon future cash flows expected to be collected. The following table displays certain information pertaining to PCI loans at the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Outstanding balance $ 12,868 $ 14,485 Carrying amount $ 11,410 $ 13,023 The following table summarizes activity in the accretable yield for the PCI loan portfolio: Three Months Ended March 31 2018 2017 (Dollars in thousands) Beginning balance $ 1,791 $ 2,370 Accretion (215 ) (307 ) Other change in expected cash flows (1) 44 216 Reclassification from nonaccretable difference for loans which have paid off (2) 22 — Ending balance $ 1,642 $ 2,279 (1) Represents changes in cash flows expected to be collected and resulting in increased interest income as a prospective yield adjustment over the remaining life of the loan(s). (2) Results in increased interest income during the period in which the loan paid off at amount greater than originally expected." id="sjs-B4">LOANS, ALLOWANCE FOR LOAN LOSSES, AND CREDIT QUALITY The following tables bifurcate the amount of loans and the allowance allocated to each loan category based on the type of impairment analysis as of the periods indicated: March 31, 2018 (Dollars in thousands) Commercial and Industrial Commercial Real Estate Commercial Construction Small Business Residential Real Estate Home Equity Other Consumer Total Financing receivables ending balance: Collectively evaluated for impairment $ 870,110 $ 3,079,910 $ 400,934 $ 132,813 $ 742,744 $ 1,044,316 $ 8,896 $ 6,279,723 Individually evaluated for impairment $ 33,104 $ 16,470 $ — $ 853 $ 13,278 $ 6,926 $ 292 $ 70,923 Purchased credit impaired loans $ — $ 5,891 $ — $ — $ 5,309 $ 210 $ — $ 11,410 Total loans by group $ 903,214 $ 3,102,271 $ 400,934 $ 133,666 $ 761,331 $ 1,051,452 $ 9,188 $ 6,362,056 (1 ) December 31, 2017 (Dollars in thousands) Commercial and Industrial Commercial Real Estate Commercial Construction Small Business Residential Real Estate Home Equity Other Consumer Total Financing receivables ending balance: Collectively evaluated for impairment $ 853,885 $ 3,093,945 $ 401,797 $ 131,667 $ 733,809 $ 1,045,053 $ 9,573 $ 6,269,729 Individually evaluated for impairment $ 34,643 $ 16,638 $ — $ 703 $ 13,684 $ 6,826 $ 307 $ 72,801 Purchased credit impaired loans $ — $ 5,978 $ — $ — $ 6,836 $ 209 $ — $ 13,023 Total loans by group $ 888,528 $ 3,116,561 $ 401,797 $ 132,370 $ 754,329 $ 1,052,088 $ 9,880 $ 6,355,553 (1 ) (1) The amount of net deferred costs on originated loans included in the ending balance was $6.4 million and $6.1 million at March 31, 2018 and December 31, 2017 , respectively. Net unamortized discounts on acquired loans not deemed to be purchased credit impaired ("PCI") included in the ending balance was $9.1 million and $9.4 million at March 31, 2018 and December 31, 2017 , respectively. The following tables summarize changes in allowance for loan losses by loan category for the periods indicated: Three Months Ended March 31, 2018 (Dollars in thousands) Commercial and Commercial Commercial Small Residential Other Consumer Total Allowance for loan losses Beginning balance $ 13,256 $ 31,453 $ 5,698 $ 1,577 $ 2,822 $ 5,390 $ 447 $ 60,643 Charge-offs (133 ) — — (24 ) (39 ) (79 ) (318 ) (593 ) Recoveries 12 20 — 9 2 34 235 312 Provision (benefit) 398 (14 ) (19 ) 31 52 14 38 500 Ending balance $ 13,533 $ 31,459 $ 5,679 $ 1,593 $ 2,837 $ 5,359 $ 402 $ 60,862 Ending balance: collectively evaluated for impairment $ 13,524 $ 31,422 $ 5,679 $ 1,590 $ 1,893 $ 5,111 $ 386 $ 59,605 Ending balance: individually evaluated for impairment $ 9 $ 37 $ — $ 3 $ 944 $ 248 $ 16 $ 1,257 Three Months Ended March 31, 2017 (Dollars in thousands) Commercial and Industrial Commercial Real Estate Commercial Construction Small Business Residential Real Estate Home Equity Other Consumer Total Allowance for loan losses Beginning balance $ 16,921 $ 30,369 $ 4,522 $ 1,502 $ 2,621 $ 5,238 $ 393 $ 61,566 Charge-offs — — — (70 ) (23 ) (14 ) (401 ) (508 ) Recoveries 187 31 — 66 12 76 288 660 Provision (benefit) (590 ) 343 501 35 106 45 160 600 Ending balance $ 16,518 $ 30,743 $ 5,023 $ 1,533 $ 2,716 $ 5,345 $ 440 $ 62,318 Ending balance: collectively evaluated for impairment $ 12,960 $ 30,570 $ 5,023 $ 1,531 $ 1,650 $ 5,110 $ 419 $ 57,263 Ending balance: individually evaluated for impairment $ 3,558 $ 173 $ — $ 2 $ 1,066 $ 235 $ 21 $ 5,055 For the purpose of estimating the allowance for loan losses, management segregates the loan portfolio into the portfolio segments detailed in the above tables. Each of these loan categories possesses unique risk characteristics that are considered when determining the appropriate level of allowance for each segment. Some of the risk characteristics unique to each loan category include: Commercial Portfolio • Commercial and Industrial : Loans in this category consist of revolving and term loan obligations extended to business and corporate enterprises for the purpose of financing working capital and/or capital investment. Collateral generally consists of pledges of business assets including, but not limited to: accounts receivable, inventory, plant and equipment, or real estate, if applicable. Repayment sources consist of primarily, operating cash flow, and secondarily, liquidation of assets. • Commercial Real Estate : Loans in this category consist of mortgage loans to finance investment in real property such as multi-family residential, commercial/retail, office, industrial, hotels, educational and healthcare facilities and other specific use properties. Loans are typically written with amortizing payment structures. Collateral values are determined based upon third party appraisals and evaluations. Loan to value ratios at origination are governed by established policy and regulatory guidelines. Repayment sources consist of, primarily, cash flow from operating leases and rents and, secondarily, liquidation of assets. • Commercial Construction : Loans in this category consist of short-term construction loans, revolving and nonrevolving credit lines and construction/permanent loans to finance the acquisition, development and construction or rehabilitation of real property. Project types include residential 1-4 family, condominium and multi-family homes, commercial/retail, office, industrial, hotels, educational and healthcare facilities and other specific use properties. Loans may be written with nonamortizing or hybrid payment structures depending upon the type of project. Collateral values are determined based upon third party appraisals and evaluations. Loan to value ratios at origination are governed by established policy and regulatory guidelines. Repayment sources vary depending upon the type of project and may consist of sale or lease of units, operating cash flows or liquidation of other assets. • Small Business: Loans in this category consist of revolving, term loan and mortgage obligations extended to sole proprietors and small businesses for purposes of financing working capital and/or capital investment. Collateral generally consists of pledges of business assets including, but not limited to, accounts receivable, inventory, plant and equipment, or real estate if applicable. Repayment sources consist primarily of operating cash flows and, secondarily, liquidation of assets. For the commercial portfolio it is the Company’s policy to obtain personal guarantees for payment from individuals holding material ownership interests of the borrowing entities. Consumer Portfolio • Residential Real Estate : Residential mortgage loans held in the Company’s portfolio are made to borrowers who demonstrate the ability to make scheduled payments with full consideration to underwriting factors such as current and expected income, employment status, current assets, other financial resources, credit history and the value of the collateral. Collateral consists of mortgage liens on 1-4 family residential properties. Residential mortgage loans also include loans to construct owner-occupied 1-4 family residential properties. • Home Equity : Home equity loans and credit lines are made to qualified individuals and are primarily secured by senior or junior mortgage liens on owner-occupied 1-4 family homes, condominiums or vacation homes. Each home equity loan has a fixed rate and is billed in equal payments comprised of principal and interest. Each home equity line of credit has a variable rate and is billed in interest-only payments during the draw period. At the end of the draw period, the home equity line of credit is billed as a percentage of the then outstanding principal balance plus all accrued interest over a predetermined repayment period, as set forth in the note. Additionally, the Company has the option of renewing each line of credit for additional draw periods. Borrower qualifications include favorable credit history combined with supportive income requirements and combined loan to value ratios within established policy guidelines. • Other Consumer: Other consumer loan products include personal lines of credit and amortizing loans made to qualified individuals for various purposes such as education, debt consolidation, personal expenses or overdraft protection. Borrower qualifications include favorable credit history combined with supportive income and collateral requirements within established policy guidelines. These loans may be secured or unsecured. Credit Quality The Company continually monitors the asset quality of the loan portfolio using all available information. Based on this information, loans demonstrating certain payment issues or other weaknesses may be categorized as adversely risk-rated, delinquent, impaired, nonperforming and/or put on nonaccrual status. Additionally, in the course of resolving such loans, the Company may choose to restructure the contractual terms of certain loans to match the borrower’s ability to repay the loan based on their current financial condition. If a restructured loan meets certain criteria, it may be categorized as a troubled debt restructuring (“TDR”). The Company reviews numerous credit quality indicators when assessing the risk in its loan portfolio. For the commercial portfolio, the Company utilizes a 10-point credit risk-rating system, which assigns a risk-grade to each loan obligation based on a number of quantitative and qualitative factors associated with a commercial or small business loan transaction. Factors considered include industry and market conditions, position within the industry, earnings trends, operating cash flow, asset/liability values, debt capacity, guarantor strength, management and controls, financial reporting, collateral, and other considerations. The risk-ratings categories are defined as follows: • 1- 6 Rating — Pass: Risk-rating grades “1” through “6” comprise those loans ranging from ‘Substantially Risk Free’ which indicates borrowers are of unquestioned credit standing and the pinnacle of credit quality, well established companies with a very strong financial condition, and loans fully secured by cash collateral, through ‘Acceptable Risk’, which indicates borrowers may exhibit declining earnings, strained cash flow, increasing or above average leverage and/or weakening market fundamentals that indicate below average asset quality, margins and market share. Collateral coverage is protective. • 7 Rating — Potential Weakness: Borrowers exhibit potential credit weaknesses or downward trends deserving management’s close attention. If not checked or corrected, these trends will weaken the Company’s asset and position. While potentially weak, currently these borrowers are marginally acceptable; no loss of principal or interest is envisioned. • 8 Rating — Definite Weakness Loss Unlikely: Borrowers exhibit well defined weaknesses that jeopardize the orderly liquidation of debt. Loan may be inadequately protected by the current net worth and paying capacity of the obligor or by the collateral pledged, if any. Normal repayment from the borrower is in jeopardy, although no loss of principal is envisioned. However, there is a distinct possibility that a partial loss of interest and/or principal will occur if the deficiencies are not corrected. Collateral coverage may be inadequate to cover the principal obligation. • 9 Rating — Partial Loss Probable: Borrowers exhibit well defined weaknesses that jeopardize the orderly liquidation of debt with the added provision that the weaknesses make collection of the debt in full, on the basis of currently existing facts, conditions, and values, highly questionable and improbable. Serious problems exist to the point where partial loss of principal is likely. • 10 Rating — Definite Loss: Borrowers deemed incapable of repayment. Loans to such borrowers are considered uncollectible and of such little value that continuation as active assets of the Company is not warranted. The credit quality of the commercial loan portfolio is actively monitored and any changes in credit quality are reflected in risk-rating changes. Risk-ratings are assigned or reviewed for all new loans, when advancing significant additions to existing relationships (over $50,000 ), at least quarterly for all actively managed loans, and any time a significant event occurs, including at renewal of the loan. The Company utilizes a comprehensive strategy for monitoring commercial credit quality. Actively managed commercial borrowers are required to provide updated financial information at least annually which is carefully evaluated for any changes in credit quality. Larger loan relationships are subject to a full annual credit review by an experienced credit analysis group, while continuous portfolio monitoring techniques are employed to evaluate changes in credit quality for smaller loan relationships. Additionally, the Company retains an independent loan review firm to evaluate the credit quality of the commercial loan portfolio. The independent loan review process achieves significant penetration into the commercial loan portfolio and reports the results of these reviews to the Audit Committee of the Board of Directors on a quarterly basis. The following tables detail the amount of outstanding principal balances relative to each of the risk-rating categories for the Company’s commercial portfolio: March 31, 2018 Category Risk Rating Commercial and Industrial Commercial Real Estate Commercial Construction Small Business Total (Dollars in thousands) Pass 1 - 6 $ 829,401 $ 2,992,497 $ 399,568 $ 131,237 $ 4,352,703 Potential weakness 7 15,910 70,879 947 1,404 89,140 Definite weakness-loss unlikely 8 51,782 38,431 419 1,022 91,654 Partial loss probable 9 6,121 464 — 3 6,588 Definite loss 10 — — — — — Total $ 903,214 $ 3,102,271 $ 400,934 $ 133,666 $ 4,540,085 December 31, 2017 Category Risk Rating Commercial and Industrial Commercial Real Estate Commercial Construction Small Business Total (Dollars in thousands) Pass 1 - 6 $ 806,331 $ 3,007,672 $ 400,964 $ 130,265 $ 4,345,232 Potential weakness 7 16,563 69,788 — 1,471 87,822 Definite weakness-loss unlikely 8 59,415 38,637 833 631 99,516 Partial loss probable 9 6,219 464 — 3 6,686 Definite loss 10 — — — — — Total $ 888,528 $ 3,116,561 $ 401,797 $ 132,370 $ 4,539,256 For the Company’s consumer portfolio, the quality of the loan is best indicated by the repayment performance of an individual borrower. However, the Company does supplement performance data with current Fair Isaac Corporation (“FICO”) scores and Loan to Value (“LTV”) estimates. Current FICO data is purchased and appended to all consumer loans on a regular basis. In addition, automated valuation services and broker opinions of value are used to supplement original value data for the residential and home equity portfolios, periodically. The following table shows the weighted average FICO scores and the weighted average combined LTV ratios as of the periods indicated below: March 31, December 31, Residential portfolio FICO score (re-scored)(1) 747 745 LTV (re-valued)(2) 58.2 % 59.2 % Home equity portfolio FICO score (re-scored)(1) 768 766 LTV (re-valued)(2)(3) 48.7 % 50.1 % (1) The average FICO scores at March 31, 2018 are based upon rescores available from February 2018 and origination score data for loans booked in March 2018. The average FICO scores at December 31, 2017 are based upon rescores available from August 2017 and origination score data for loans booked between September and December 2017. (2) The combined LTV ratios for March 31, 2018 are based upon updated automated valuations as of February 2018, when available or the most current valuation data available. The combined LTV ratios for December 31, 2017 are based upon updated automated valuations as of August 2017, when available, or the most current valuation data available. The updated automated valuations provides new information on loans that may be available since the previous valuation was obtained. If no new information is available, the valuation will default to the previously obtained data or most recent appraisal. (3) For home equity loans and lines in a subordinate lien, the LTV data represents a combined LTV, taking into account the senior lien data for loans and lines. Asset Quality The Company’s philosophy toward managing its loan portfolios is predicated upon careful monitoring, which stresses early detection and response to delinquent and default situations. Delinquent loans are managed by a team of collection specialists and the Company seeks to make arrangements to resolve any delinquent or default situation over the shortest possible time frame. As a general rule, loans more than 90 days past due with respect to principal or interest are classified as nonaccrual loans. The Company also may use discretion regarding other loans over 90 days delinquent if the loan is well secured and/or in process of collection. The following table shows information regarding nonaccrual loans at the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Commercial and industrial $ 30,751 $ 32,055 Commercial real estate 2,997 3,123 Small business 412 230 Residential real estate 7,646 8,129 Home equity 5,858 6,022 Other consumer 40 71 Total nonaccrual loans (1) $ 47,704 $ 49,630 (1) Included in these amounts were $5.6 million and $6.1 million of nonaccruing TDRs at March 31, 2018 and December 31, 2017 , respectively. The following table shows information regarding foreclosed residential real estate property at the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Foreclosed residential real estate property held by the creditor $ 358 $ 612 Recorded investment in mortgage loans collateralized by residential real estate property that are in the process of foreclosure $ 2,094 $ 2,971 The following tables show the age analysis of past due financing receivables as of the dates indicated: March 31, 2018 30-59 days 60-89 days 90 days or more Total Past Due Total Financing Receivables Recorded Investment >90 Days and Accruing Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Current (Dollars in thousands) Loan Portfolio Commercial and industrial 4 $ 411 2 $ 101 14 $ 30,638 20 $ 31,150 $ 872,064 $ 903,214 $ — Commercial real estate 9 3,127 4 1,253 6 1,413 19 5,793 3,096,478 3,102,271 — Commercial construction 2 855 — — — — 2 855 400,079 400,934 — Small business 11 107 8 69 23 347 42 523 133,143 133,666 — Residential real estate 13 1,834 7 1,100 19 3,052 39 5,986 755,345 761,331 — Home equity 22 2,266 8 882 26 2,440 56 5,588 1,045,864 1,051,452 — Other consumer (1) 221 104 7 2 18 20 246 126 9,062 9,188 9 Total 282 $ 8,704 36 $ 3,407 106 $ 37,910 424 $ 50,021 $ 6,312,035 $ 6,362,056 $ 9 December 31, 2017 30-59 days 60-89 days 90 days or more Total Past Due Total Financing Receivables Recorded Investment >90 Days and Accruing Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Current (Dollars in thousands) Loan Portfolio Commercial and industrial 2 $ 195 2 $ 370 14 $ 32,007 18 $ 32,572 $ 855,956 $ 888,528 $ — Commercial real estate 7 3,060 — — 9 1,793 16 4,853 3,111,708 3,116,561 — Commercial construction — — — — — — — — 401,797 401,797 — Small business 17 339 11 144 10 57 38 540 131,830 132,370 — Residential real estate 6 870 13 2,385 22 3,471 41 6,726 747,603 754,329 — Home equity 22 1,310 6 451 20 2,025 48 3,786 1,048,302 1,052,088 — Other consumer (1) 265 197 16 27 17 45 298 269 9,611 9,880 8 Total 319 $ 5,971 48 $ 3,377 92 $ 39,398 459 $ 48,746 $ 6,306,807 $ 6,355,553 $ 8 (1) Other consumer portfolio is inclusive of deposit account overdrafts recorded as loan balances. Troubled Debt Restructurings In the course of resolving nonperforming loans, the Bank may choose to restructure the contractual terms of certain loans. The Bank attempts to work out an alternative payment schedule with the borrower in order to avoid foreclosure actions. Any loans that are modified are reviewed by the Bank to identify if a TDR has occurred, which is when, for economic or legal reasons related to a borrower’s financial difficulties, the Bank grants a concession to the borrower that it would not otherwise consider. Terms may be modified to fit the ability of the borrower to repay in line with its current financial status and the restructuring of the loan may include the transfer of assets from the borrower to satisfy the debt, a modification of loan terms, or a combination of the two. The following table shows the Company’s total TDRs and other pertinent information as of the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) TDRs on accrual status $ 25,617 $ 25,852 TDRs on nonaccrual 5,637 6,067 Total TDRs $ 31,254 $ 31,919 Amount of specific reserves included in the allowance for loan losses associated with TDRs $ 1,257 $ 1,342 Additional commitments to lend to a borrower who has been a party to a TDR $ 600 $ 487 The Company’s policy is to have any restructured loan which is on nonaccrual status prior to being modified remain on nonaccrual status for six months subsequent to being modified before management considers its return to accrual status. If the restructured loan is on accrual status prior to being modified, it is reviewed to determine if the modified loan should remain on accrual status. Additionally, loans classified as TDRs are adjusted to reflect the changes in value of the recorded investment in the loan, if any, resulting from the granting of a concession. For all residential loan modifications, the borrower must perform during a 90 day trial period before the modification is finalized. The following tables show the modifications which occurred during the periods indicated and the change in the recorded investment subsequent to the modifications occurring: Three Months Ended March 31, 2018 Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment (1) (Dollars in thousands) Troubled debt restructurings Commercial real estate 1 445 445 Home equity 2 242 242 Total 3 $ 687 $ 687 Three Months Ended March 31, 2017 Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment (1) (Dollars in thousands) Troubled debt restructurings Commercial and industrial 2 $ 80 $ 80 Commercial real estate 4 934 934 Small business 4 143 143 Home equity 2 140 140 Total 12 $ 1,297 $ 1,297 (1) The post-modification balances represent the legal principal balance of the loan on the date of modification. These amounts may show an increase when modifications include a capitalization of interest. The following table shows the Company’s post-modification balance of TDRs listed by type of modification during the periods indicated: Three Months Ended March 31 2018 2017 (Dollars in thousands) Extended maturity $ 445 $ 1,207 Court ordered concession 242 90 Total $ 687 $ 1,297 The Company considers a loan to have defaulted when it reaches 90 days past due. There were no loans modified during the preceding twelve months that had subsequently defaulted during the three months ended March 31, 2018 and 2017 . All TDR loans are considered impaired and therefore are subject to a specific review for impairment. The impairment analysis appropriately discounts the present value of the anticipated cash flows by the loan’s contractual rate of interest in effect prior to the loan’s modification. The amount of impairment, if any, is recorded as a specific loss allocation to each individual loan in the allowance for loan losses. Commercial loans (commercial and industrial, commercial construction, commercial real estate and small business loans), residential loans, and home equity loans that have been classified as TDRs and which subsequently default are reviewed to determine if the loan should be deemed collateral dependent. In such an instance, any shortfall between the value of the collateral and the carrying value of the loan is determined by measuring the recorded investment in the loan against the fair value of the collateral less costs to sell. The Company charges off the amount of any confirmed loan loss in the period when the loans, or portion of loans, are deemed uncollectible. Smaller balance consumer TDR loans are reviewed for performance to determine when a charge-off is appropriate. Impaired Loans A loan is considered impaired when, based on current information and events, it is probable that the Company will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered by management in determining impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Loans that experience insignificant payment delays and payment shortfalls generally are not classified as impaired. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. The tables below set forth information regarding the Company’s impaired loans by loan portfolio at the dates indicated: March 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 32,878 $ 38,785 $ — Commercial real estate 14,747 15,894 — Small business 727 797 — Residential real estate 4,234 4,367 — Home equity 5,248 5,357 — Other consumer 85 86 — Subtotal 57,919 65,286 — With an allowance recorded Commercial and industrial $ 226 $ 226 $ 9 Commercial real estate 1,723 1,723 37 Small business 126 132 3 Residential real estate 9,044 9,790 944 Home equity 1,678 1,919 248 Other consumer 207 209 16 Subtotal 13,004 13,999 1,257 Total $ 70,923 $ 79,285 $ 1,257 December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 34,267 $ 38,329 $ — Commercial real estate 13,245 14,374 — Small business 556 619 — Residential real estate 4,264 4,397 — Home equity 4,950 5,056 — Other consumer 91 92 — Subtotal 57,373 62,867 — With an allowance recorded Commercial and industrial $ 376 $ 376 $ 10 Commercial real estate 3,393 3,399 42 Small business 147 153 1 Residential real estate 9,420 10,154 1,007 Home equity 1,876 2,110 265 Other consumer 216 217 17 Subtotal 15,428 16,409 1,342 Total $ 72,801 $ 79,276 $ 1,342 The following tables set forth information regarding interest income recognized on impaired loans, by portfolio, for the periods indicated: Three Months Ended March 31, 2018 Average Recorded Investment Interest Income Recognized (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 33,784 $ 31 Commercial real estate 14,855 157 Small business 710 5 Residential real estate 4,254 53 Home equity 5,280 53 Other consumer 87 1 Subtotal 58,970 300 With an allowance recorded Commercial and industrial $ 227 $ 2 Commercial real estate 1,730 24 Small business 131 2 Residential real estate 9,060 71 Home equity 1,688 12 Other consumer 211 2 Subtotal 13,047 113 Total $ 72,017 $ 413 Three Months Ended March 31, 2017 Average Recorded Investment Interest Income Recognized (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 39,193 $ 208 Commercial real estate 9,678 91 Small business 304 3 Residential real estate 3,671 43 Home equity 4,323 44 Other consumer 120 2 Subtotal 57,289 391 With an allowance recorded Commercial and industrial $ 10,178 $ 4 Commercial real estate 5,189 50 Small business 457 5 Residential real estate 10,057 85 Home equity 1,402 13 Other consumer 245 2 Subtotal 27,528 159 Total $ 84,817 $ 550 Purchased Credit Impaired Loans Certain loans acquired by the Company may have shown evidence of deterioration of credit quality since origination and it was therefore deemed unlikely that the Company would be able to collect all contractually required payments. As such, these loans were deemed to be PCI loans and the carrying value and prospective income recognition are predicated upon future cash flows expected to be collected. The following table displays certain information pertaining to PCI loans at the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Outstanding balance $ 12,868 $ 14,485 Carrying amount $ 11,410 $ 13,023 The following table summarizes activity in the accretable yield for the PCI loan portfolio: Three Months Ended March 31 2018 2017 (Dollars in thousands) Beginning balance $ 1,791 $ 2,370 Accretion (215 ) (307 ) Other change in expected cash flows (1) 44 216 Reclassification from nonaccretable difference for loans which have paid off (2) 22 — Ending balance $ 1,642 $ 2,279 (1) Represents changes in cash flows expected to be collected and resulting in increased interest income as a prospective yield adjustment over the remaining life of the loan(s). (2) Results in increased interest income during the period in which the loan paid off at amount greater than originally expected.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE Earnings per share consisted of the following components for the periods indicated: Three Months Ended March 31 2018 2017 (Dollars in thousands, except per share data) Net income $ 27,555 $ 20,725 Weighted Average Shares Basic shares 27,486,573 27,029,640 Effect of dilutive securities 67,381 81,283 Diluted shares 27,553,954 27,110,923 Net income per share Basic EPS $ 1.00 $ 0.77 Effect of dilutive securities — (0.01 ) Diluted EPS $ 1.00 $ 0.76 The following table illustrates the options to purchase common stock or shares of performance-based restricted stock that were excluded from the calculation of diluted earnings per share because they were anti-dilutive for the periods indicated: Three Months Ended March 31 2018 2017 Stock options 143 — Performance-based restricted stock — 127

Stock Based Compensation

Stock Based Compensation	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK BASED COMPENSATION	STOCK BASED COMPENSATION Time Vested Restricted Stock Awards During the three months ended March 31, 2018 , the Company made the following awards of restricted stock: Date Shares Granted Plan Grant Date Fair Value Per Share Vesting Period 2/15/2018 39,950 2005 Employee Stock Plan $ 71.75 Ratably over 5 years from grant date 2/27/2018 1,150 2005 Employee Stock Plan $ 72.60 Ratably over 5 years from grant date The fair value of the restricted stock awards is based upon the average of the high and low price at which the Company’s common stock traded on the date of grant. The holders of restricted stock awards are entitled to receive dividends and to vote from and as of the date of grant. Performance-Based Restricted Stock Awards On February 15, 2018 , the Company granted 16,300 performance-based restricted stock awards to certain executive level employees. These performance-based restricted stock awards were issued from the 2005 Employee Stock Plan and were determined to have a grant date fair value per share of $71.75 , determined by the average of the high and low price at which the Company's common stock traded on the date of grant. The number of shares to be vested will be contingent upon the Company's attainment of certain performance measures outlined in the award agreement and will be measured as of the end of the three year performance period, January 1, 2018 through December 31, 2020. The awards will vest upon the earlier of the date on which it is determined if the performance goal is achieved subsequent to the performance period or March 31, 2021. These awards will be accounted for as equity awards due to the nature of these awards and the fact that these shares will not be settled in cash. The holders of these awards are not entitled to receive dividends or vote until the shares are vested. On February 27, 2018 , the performance-based restricted stock awards that were awarded on February 12, 2015 vested at 100% of the maximum target shares awarded, or 16,427 shares. Stock Options The Company did not grant any awards of options to purchase shares of common stock during the three months ended March 31, 2018 .

Repurchase Agreements Disclosur

Repurchase Agreements Disclosure of Repurchase Agreements (Notes)	3 Months Ended
	Mar. 31, 2018
Disclosure of Repurchase Agreements [Abstract]
Repurchase Agreements, Resale Agreements, Securities Borrowed, and Securities Loaned Disclosure [Text Block]	REPURCHASE AGREEMENTS The Company can raise additional liquidity by entering into repurchase agreements at its discretion. These repurchases are accounted for as a secured borrowing transaction for accounting purposes. Payments on such borrowings are interest only until the scheduled repurchase date. In a repurchase agreement the Company is subject to the risk that the purchaser may default at maturity and not return the securities underlying the agreements. In order to minimize this potential risk, the Company enters into repurchase agreements that stipulate that the securities underlying the agreement are not delivered to the customer and instead are held in segregated safekeeping accounts by the Company's safekeeping agents. The table below sets forth information regarding the Company’s repurchase agreements allocated by source of collateral at the dates indicated: March 31, December 31, (Dollars in thousands) Sources of collateral U.S. government agency securities $ 13,200 $ 16,867 Agency mortgage-backed securities 55,946 51,273 Agency collateralized mortgage obligations 68,768 94,539 Total customer repurchase agreements (1) $ 137,914 $ 162,679 (1) All customer repurchase agreements have an overnight and continuous maturity date. For further information regarding the Company's repurchase agreements see Note 9 - Balance Sheet Offsetting .

Derivatives and Hedging Activit

Derivatives and Hedging Activities	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVES AND HEDGING ACTIVITIES	DERIVATIVE AND HEDGING ACTIVITIES The Company early adopted ASU 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities as of January 1, 2018 to incorporate the new standard’s alignment of hedge accounting qualifications with the Company’s interest rate risk management with respect to new hedges entered into during the first quarter of 2018. This new standard was adopted under a modified retrospective transition, resulting in no changes to the accounting for hedge positions entered in to prior to January 1, 2018. The Company’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the Company’s known or expected cash receipts and its known or expected cash payments principally to manage the Company’s interest rate risk. Additionally, the Company enters into interest rate derivatives and foreign exchange contracts to accommodate the business requirements of its customers (“customer related positions”). The Company minimizes the market and liquidity risks of customer related positions by entering into similar offsetting positions with broker-dealers. Derivative instruments are carried at fair value in the Company’s financial statements. The accounting for changes in the fair value of a derivative instrument is dependent upon whether or not it qualifies as a hedge for accounting purposes, and further, by the type of hedging relationship. The Company does not enter into proprietary trading positions for any derivatives. Interest Rate Positions The Company may utilize various interest rate derivatives as hedging instruments against interest rate risk associated with the Company’s borrowings and loan portfolios. An interest rate derivative is an agreement whereby one party agrees to pay a floating rate of interest on a notional principal amount in exchange for receiving a fixed rate of interest on the same notional amount, for a predetermined period of time, from a second party. The amounts relating to the notional principal amount are not actually exchanged. The following tables reflect the Company's derivative positions for the periods indicated below for interest rate derivatives which qualify as cash flow hedges for accounting purposes: March 31, 2018 Notional Amount Trade Date Effective Date Maturity Date Receive (Variable) Index Current Rate Received Pay Fixed Swap Rate Fair Value (Dollars in thousands) $ 25,000 12/9/2008 12/10/2008 12/10/2018 3 Month LIBOR 2.07 % 2.94 % $ (118 ) 25,000 4/1/2016 1/17/2017 12/15/2021 3 Month LIBOR 2.12 % 1.36 % 1,128 25,000 4/1/2016 1/17/2017 12/15/2021 3 Month LIBOR 2.12 % 1.36 % 1,116 25,000 7/18/2017 8/15/2017 8/15/2022 3 Month LIBOR 1.87 % 1.88 % 796 Notional Amount Trade Date Effective Date Maturity Date Pay (Variable) Index Current Rate Paid Receive Fixed Swap Rate Fair Value 50,000 1/9/2018 1/16/2018 1/15/2023 1 Month LIBOR 1.78 % 2.24 % $ (678 ) Notional Amount Trade Date Effective Date Maturity Date Pay (Variable) Index Current Rate Paid Receive Fixed Swap Rate Cap - Floor Fair Value 50,000 1/9/2018 1/16/2018 1/15/2022 1 Month LIBOR 1.78 % 2.75% - 1.80% $ (270 ) $ 1,974 December 31, 2017 Notional Amount Trade Date Effective Date Maturity Date Receive (Variable) Index Current Rate Received Pay Fixed Swap Rate Fair Value (Dollars in thousands) $ 25,000 12/9/2008 12/10/2008 12/10/2018 3 Month LIBOR 1.54 % 2.94 % $ (264 ) 25,000 4/1/2016 1/17/2017 12/15/2021 3 Month LIBOR 1.59 % 1.36 % 772 25,000 4/1/2016 1/17/2017 12/15/2021 3 Month LIBOR 1.59 % 1.36 % 763 25,000 7/18/2017 8/15/2017 8/15/2022 3 Month LIBOR 1.42 % 1.88 % 345 $ 1,616 The maximum length of time over which the Company is currently hedging its exposure to the variability in future cash flows for forecasted transactions related to the payment of variable interest on existing financial instruments is five years. For derivative instruments that are designated and qualify as cash flow hedging instruments, the effective portion of the gains or losses is reported as a component of other comprehensive income ("OCI"), and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. The Company expects approximately $53,000 and $656,000 (pre-tax) to be reclassified as an offset to interest income and an offset to interest expense, respectively, from OCI related to the Company’s cash flow hedges in the next twelve months. This reclassification is due to anticipated payments that will be made and/or received on the swaps based upon the forward curve as of March 31, 2018 . The Company recognized $61,000 of net amortization income that was an offset to interest expense related to previously terminated swaps for the three month periods ended March 31, 2018 and 2017 . The Company had no fair value hedges as of March 31, 2018 or December 31, 2017 . Customer Related Positions Loan level derivatives, primarily interest rate swaps, offered to commercial borrowers through the Company’s loan level derivative program do not qualify as hedges for accounting purposes. The Company believes that its exposure to commercial customer derivatives is limited because these contracts are simultaneously matched at inception with an offsetting dealer transaction. The commercial customer derivative program allows the Company to retain variable-rate commercial loans while allowing the customer to synthetically fix the loan rate by entering into a variable-to-fixed interest rate swap. Foreign exchange contracts offered to commercial borrowers through the Company’s derivative program do not qualify as hedges for accounting purposes. The Company acts as a seller and buyer of foreign exchange contracts to accommodate its customers. To mitigate the market and liquidity risk associated with these derivatives, the Company enters into similar offsetting positions. The following tables reflect the Company’s customer related derivative positions for the periods indicated below for those derivatives not designated as hedging: Notional Amount Maturing Number of Positions (1) Less than 1 year Less than 2 years Less than 3 years Less than 4 years Thereafter Total Fair Value March 31, 2018 (Dollars in thousands) Loan level swaps Receive fixed, pay variable 248 $ 34,081 $ 95,894 $ 173,172 $ 59,531 $ 602,621 $ 965,299 $ (11,404 ) Pay fixed, receive variable 233 $ 34,081 $ 95,894 $ 173,172 $ 59,531 $ 602,621 $ 965,299 $ 11,390 Foreign exchange contracts Buys foreign currency, sells U.S. currency 18 $ 33,089 $ — $ — $ — $ — $ 33,089 $ 770 Buys U.S. currency, sells foreign currency 18 $ 33,089 $ — $ — $ — $ — $ 33,089 $ (751 ) December 31, 2017 (Dollars in thousands) Loan level swaps Receive fixed, pay variable 246 $ 36,023 $ 61,500 $ 152,287 $ 111,147 $ 591,385 $ 952,342 $ 3,875 Pay fixed, receive variable 231 $ 36,023 $ 61,500 $ 152,287 $ 111,147 $ 591,385 $ 952,342 $ (3,880 ) Foreign exchange contracts Buys foreign currency, sells U.S. currency 15 $ 26,382 $ 3,780 $ — $ — $ — $ 30,162 $ 1,202 Buys U.S. currency, sells foreign currency 15 $ 26,382 $ 3,780 $ — $ — $ — $ 30,162 $ (1,188 ) (1) The Company may enter into one dealer swap agreement which offsets multiple commercial borrower swap agreements. Mortgage Derivatives Prior to closing and funding certain 1- 4 family residential mortgage loans, an interest rate lock commitment is generally extended to the borrower. During the period from commitment date to closing date, the Company is subject to the risk that market rates of interest may change. If market rates rise, investors generally will pay less to purchase such loans resulting in a reduction in the gain on sale of the loans or, possibly, a loss. In an effort to mitigate such risk, forward delivery sales commitments are executed, under which the Company agrees to deliver whole mortgage loans to various investors. These forward commitments carry a market price that has a strong inverse relationship to that of mortgage prices. Certain assumptions, including pull through rates and rate lock periods, are used in managing the existing and future hedges. The accuracy of underlying assumptions will impact the ultimate effectiveness of any hedging strategies. The change in fair value on the interest rate lock commitments and forward delivery sale commitments are recorded in current period earnings as a component of mortgage banking income. In addition, the Company has elected the fair value option to carry loans held for sale at fair value. The change in fair value of loans held for sale is recorded in current period earnings as a component of mortgage banking income in accordance with the Company's fair value election. The change in fair value associated with loans held for sale was a decrease of $26,000 and $147,000 for the three month periods ended March 31, 2018 and 2017 , respectively. These amounts were offset in earnings by the change in the fair value of mortgage derivatives. Additionally, the aggregate amount of net realized gains or losses on sales of such loans included within mortgage banking income was $782,000 and $980,000 for the three month periods ended March 31, 2018 and 2017 , respectively. The table below presents the fair value of the Company’s derivative financial instruments, as well as their classification on the balance sheet at the periods indicated: Asset Derivatives Liability Derivatives Fair Value at Fair Value at Fair Value at Fair Value at Balance Sheet March 31 December 31 Balance Sheet March 31 December 31 (Dollars in thousands) Derivatives designated as hedges Interest rate derivatives Other assets $ 3,040 $ 1,880 Other liabilities $ 1,066 $ 264 Derivatives not designated as hedges Customer Related Positions Loan level derivatives Other assets $ 16,916 $ 14,236 Other liabilities $ 16,930 $ 14,241 Foreign exchange contracts Other assets 914 1,202 Other liabilities 895 1,188 Mortgage Derivatives Interest rate lock commitments Other assets 151 149 Other liabilities — — Forward sales agreements Other assets 19 9 Other liabilities — — $ 18,000 $ 15,596 $ 17,825 $ 15,429 Total $ 21,040 $ 17,476 $ 18,891 $ 15,693 The table below presents the effect of the Company’s derivative financial instruments included in OCI and current earnings for the periods indicated: Three Months Ended March 31 2018 2017 (Dollars in thousands) Derivatives designated as hedges Gain in OCI on derivatives (effective portion), net of tax $ 215 $ 89 Gain (loss) reclassified from OCI into interest income or interest expense (effective portion) $ 90 $ (93 ) Loss recognized in income on derivatives (ineffective portion and amount excluded from effectiveness testing) Interest expense $ — $ — Other expense — — Total $ — $ — Derivatives not designated as hedges Changes in fair value of customer related positions Other income $ 9 $ (7 ) Other expense (13 ) (6 ) Changes in fair value of mortgage derivatives Mortgage banking income 12 50 Total $ 8 $ 37 The Company's derivative agreements with institutional counterparties contain various credit-risk related contingent provisions, such as requiring the Company to maintain a well-capitalized capital position. If the Company fails to meet these conditions, the counterparties could request the Company make immediate payment or demand that the Company provide immediate and ongoing full collateralization on derivative positions in net liability positions. The aggregate fair value of all derivative instruments with credit-risk related contingent features that were in a net liability position was $288,000 and $4.2 million at March 31, 2018 and December 31, 2017 , respectively. Although none of the contingency provisions have applied as of March 31, 2018 and December 31, 2017 , the Company has posted collateral to offset the net liability exposures with institutional counterparties. By using derivatives, the Company is exposed to credit risk to the extent that counterparties to the derivative contracts do not perform as required. Should a counterparty fail to perform under the terms of a derivative contract, the Company's credit exposure on interest rate swaps is limited to the net positive fair value and accrued interest of all swaps with each counterparty. The Company seeks to minimize counterparty credit risk through credit approvals, limits, monitoring procedures, and obtaining collateral, where appropriate. Institutional counterparties must have an investment grade credit rating and be approved by the Company's Board of Directors. As such, management believes the risk of incurring credit losses on derivative contracts with institutional counterparties is remote. The Company's exposure relating to institutional counterparties was $17.4 million and $7.1 million at March 31, 2018 and December 31, 2017 , respectively. The Company’s exposure relating to customer counterparties was approximately $3.2 million and $9.5 million at March 31, 2018 and December 31, 2017 , respectively. Credit exposure may be reduced by the value of collateral pledged by the counterparty.

Balance Sheet Offsetting

Balance Sheet Offsetting	3 Months Ended
	Mar. 31, 2018
Offsetting [Abstract]
Balance Sheet Offsetting Disclosure [Text Block]	BALANCE SHEET OFFSETTING The Company does not offset fair value amounts recognized for derivative instruments or repurchase agreements. The Company does net the amount recognized for the right to reclaim cash collateral against the obligation to return cash collateral arising from derivative instruments executed with the same counterparty under a master netting arrangement. Collateral legally required to be maintained at dealer banks by the Company is monitored and adjusted as necessary. The following tables present the Company's asset and liability derivative positions and the potential effect of netting arrangements on its financial position, as of the periods indicated: Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts Recognized in the Statement of Financial Position Gross Amounts Offset in the Statement of Financial Position Net Amounts Presented in the Statement of Financial Position Financial Instruments (1) Collateral Pledged (Received) Net Amount March 31, 2018 (Dollars in thousands) Derivative Assets Interest rate swaps $ 3,040 $ — $ 3,040 $ 948 $ (1,128 ) $ 964 Loan level derivatives 16,916 — 16,916 2,767 (8,945 ) 5,204 Customer foreign exchange contracts 914 — 914 — — 914 $ 20,870 $ — $ 20,870 $ 3,715 $ (10,073 ) $ 7,082 Derivative Liabilities Interest rate swaps $ 1,066 $ — $ 1,066 $ 948 $ 118 $ — Loan level derivatives 16,930 — 16,930 2,767 141 14,022 Customer foreign exchange contracts 895 — 895 — — 895 $ 18,891 $ — $ 18,891 $ 3,715 $ 259 $ 14,917 Customer repurchase agreements 137,914 — 137,914 — 137,914 — (1) Reflects offsetting derivative positions with the same counterparty. Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts Recognized in the Statement of Financial Position Gross Amounts Offset in the Statement of Financial Position Net Amounts Presented in the Statement of Financial Position Financial Instruments (1) Collateral Pledged (Received) Net Amount December 31, 2017 (Dollars in thousands) Derivative Assets Interest rate swaps $ 1,880 $ — $ 1,880 $ 805 $ — $ 1,075 Loan level derivatives 14,236 — 14,236 4,578 — 9,658 Customer foreign exchange contracts 1,202 — 1,202 — — 1,202 $ 17,318 $ — $ 17,318 $ 5,383 $ — $ 11,935 Derivative Liabilities Interest rate swaps $ 264 $ — $ 264 $ — $ 264 $ — Loan level derivatives 14,241 — 14,241 5,383 3,675 5,183 Customer foreign exchange contracts 1,188 — 1,188 — — 1,188 $ 15,693 $ — $ 15,693 $ 5,383 $ 3,939 $ 6,371 Customer repurchase agreements 162,679 — 162,679 — 162,679 — (1) Reflects offsetting derivative positions with the same counterparty.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Fair value is a market-based measure considered from the perspective of a market participant rather than an entity-specific measure. Therefore, even when market assumptions are not readily available, the assumptions applied by the Company when determining fair value reflect those that the Company determines market participants would use to price the asset or liability at the measurement date. If there has been a significant decrease in the volume and level of activity for the asset or liability, regardless of the valuation technique(s) used, the objective of a fair value measurement remains the same. Fair value is the price that would be received if the asset were to be sold or that would be or paid if liability were to be transferred in an orderly market transaction (that is, not a forced liquidation or distressed sale) between market participants at the measurement date under current market conditions. When determining fair value, the Company considers pricing information and other inputs that are current as of the measurement date. In periods of market dislocation, the observability of prices and other inputs may be reduced for certain instruments, or not available at all. The unavailability or reduced availability of pricing or other input information could cause an instrument to be reclassified from one level to another. The Fair Value Measurements and Disclosures Topic of the FASB ASC defines fair value and establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy under the Fair Value Measurements and Disclosures Topic of the FASB ASC are described below: Level 1 – Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity has the ability to access at the measurement date. Level 2 – Valuations based on quoted prices in markets that are not active or for which all significant inputs are observable, either directly or indirectly. Level 3 – Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable. To the extent that valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Valuation Techniques There have been no changes in the valuation techniques used during the current period. Securities Trading and Equity Securities These equity securities are valued based on market quoted prices. These securities are categorized in Level 1 as they are actively traded and no valuation adjustments have been applied. U.S. Government Agency Securities Fair value is estimated using either multi-dimensional spread tables or benchmarks. The inputs used include benchmark yields, reported trades, and broker/dealer quotes. These securities are classified as Level 2. Agency Mortgage-Backed Securities Fair value is estimated using either a matrix or benchmarks. The inputs used include benchmark yields, reported trades, broker/dealer quotes, and issuer spreads. These securities are categorized as Level 2. Agency Collateralized Mortgage Obligations and Small Business Administration Pooled Securities The valuation model for these securities is volatility-driven and ratings based, and uses multi-dimensional spread tables. The inputs used include benchmark yields, reported trades, new issue data, broker dealer quotes, and collateral performance. If there is at least one significant model assumption or input that is not observable, these securities are categorized as Level 3 within the fair value hierarchy; otherwise, they are classified as Level 2. State, County, and Municipal Securities The fair value is estimated using a valuation matrix with inputs including bond interest rate tables, recent transactions, and yield relationships. These securities are categorized as Level 2. Single and Pooled Issuer Trust Preferred Securities The fair value of trust preferred securities, including pooled and single issuer preferred securities, is estimated using external pricing models, discounted cash flow methodologies or similar techniques. The inputs used in these valuations include benchmark yields, reported trades, new issue data, broker dealer quotes, and collateral performance. If there is at least one significant model assumption or input that is not observable, these securities are classified as Level 3 within the fair value hierarchy; otherwise, they are classified as Level 2. Loans Held for Sale The Company has elected the fair value option to account for originated closed loans intended for sale. The fair value is measured on an individual loan basis using quoted market prices and when not available, comparable market value or discounted cash flow analysis may be utilized. These assets are typically classified as Level 2. Derivative Instruments Derivatives The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. The Company incorporates credit valuation adjustments to appropriately reflect nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings. Additionally, in conjunction with fair value measurement guidance, the Company has made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio. Although the Company has determined that the majority of the inputs used to value its interest rate derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its interest rate derivatives may also utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by the Company and its counterparties. However, as of March 31, 2018 and December 31, 2017 , the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are properly classified as Level 2. Mortgage Derivatives The fair value of mortgage derivatives is determined based on current market prices for similar assets in the secondary market and, therefore, classified as Level 2 within the fair value hierarchy. Impaired Loans Collateral dependent loans that are deemed to be impaired are valued based upon the lower of cost or fair value of the underlying collateral less costs to sell. The inputs used in the appraisals of the collateral are not always observable, and in such cases the loans may be classified as Level 3 within the fair value hierarchy; otherwise, they are classified as Level 2. Other Real Estate Owned and Other Foreclosed Assets Other Real Estate Owned ("OREO") and Other Foreclosed Assets are valued at the lower of cost or fair value of the property, less estimated costs to sell. The fair values are generally estimated based upon recent appraisal values of the property less costs to sell the property. Certain inputs used in appraisals are not always observable, and therefore OREO and Other Foreclosed Assets may be classified as Level 3 within the fair value hierarchy. Goodwill and Other Intangible Assets Goodwill and other intangible assets are subject to impairment testing. The Company conducts an annual impairment test of goodwill in the third quarter of each year, or more frequently if necessary. Other intangible assets are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. To estimate the fair value of goodwill and, if necessary, other intangible assets, the Company utilizes both a comparable analysis of relevant price multiples in recent market transactions and discounted cash flow analysis. Both valuation models require a significant degree of management judgment. In the event the fair value as determined by the valuation model is less than the carrying value, the intangibles may be impaired. If the impairment testing resulted in impairment, the Company would classify the impaired goodwill and other intangible assets subjected to nonrecurring fair value adjustments as Level 3. Assets and liabilities measured at fair value on a recurring and nonrecurring basis were as follows as of the dates indicated: Fair Value Measurements at Reporting Date Using Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) March 31, 2018 (Dollars in thousands) Recurring fair value measurements Assets Trading securities $ 1,601 $ 1,601 $ — $ — Equity securities 20,075 20,075 — — Securities available for sale U.S. Government agency securities 34,943 — 34,943 — Agency mortgage-backed securities 223,211 — 223,211 — Agency collateralized mortgage obligations 135,192 — 135,192 — State, county, and municipal securities 2,254 — 2,254 — Single issuer trust preferred securities issued by banks and insurers 2,005 — 2,005 — Pooled trust preferred securities issued by banks and insurers 1,655 — — 1,655 Small business administration pooled securities 46,490 — 46,490 — Loans held for sale 3,937 — 3,937 — Derivative instruments 21,040 — 21,040 — Liabilities Derivative instruments 18,891 — 18,891 — Total recurring fair value measurements $ 473,512 $ 21,676 $ 450,181 $ 1,655 Nonrecurring fair value measurements Assets Collateral dependent impaired loans $ 32,113 $ — $ — $ 32,113 Other real estate owned and other foreclosed assets 358 — — 358 Total nonrecurring fair value measurements $ 32,471 $ — $ — $ 32,471 Fair Value Measurements at Reporting Date Using Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2017 (Dollars in thousands) Recurring fair value measurements Assets Trading securities $ 1,324 $ 1,324 $ — $ — Equity securities 20,584 20,584 — — Securities available for sale U.S. Government agency securities 35,430 — 35,430 — Agency mortgage-backed securities 215,764 — 215,764 — Agency collateralized mortgage obligations 122,012 — 122,012 — State, county, and municipal securities 2,274 — 2,274 — Single issuer trust preferred securities issued by banks and insurers 2,016 — 2,016 — Pooled trust preferred securities issued by banks and insurers 1,640 — — 1,640 Small business administration pooled securities 47,778 — 47,778 — Loans held for sale 4,768 — 4,768 — Derivative instruments 17,476 — 17,476 — Liabilities Derivative instruments 15,693 — 15,693 — Total recurring fair value measurements $ 455,373 $ 21,908 $ 431,825 $ 1,640 Nonrecurring fair value measurements: Assets Collateral dependent impaired loans $ 33,567 $ — $ — $ 33,567 Other real estate owned and other foreclosed assets 612 — — 612 Total nonrecurring fair value measurements $ 34,179 $ — $ — $ 34,179 The table below presents a reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3), which were valued using pricing models and discounted cash flow methodologies, as of the dates indicated: Three Months Ended March 31 2018 2017 (Dollars in thousands) Pooled Trust Preferred Securities Beginning balance $ 1,640 $ 1,584 Gains and (losses) (realized/unrealized) Included in other comprehensive income 21 11 Settlements (6 ) 1 Ending balance $ 1,655 $ 1,596 It is the Company’s policy to recognize the transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers between the levels of the fair value hierarchy for any assets or liabilities measured at fair value on a recurring basis during the three month periods ended March 31, 2018 or 2017 . The following table sets forth certain unobservable inputs regarding the Company’s investment in securities that are classified as Level 3 for the periods indicated: March 31 December 31 March 31 December 31 March 31 December 31 Valuation Technique Fair Value Unobservable Inputs Range Weighted Average (Dollars in thousands) Discounted cash flow methodology Pooled trust preferred securities $ 1,655 $ 1,640 Cumulative prepayment 0% - 60% 0% - 61% 2.4% 2.5% Cumulative default 5% - 100% 5% - 100% 12.3% 12.4% Loss given default 85% - 100% 85% - 100% 94.4% 94.3% Cure given default 0% - 75% 0% - 75% 60.9% 60.9% Appraisals of collateral(1) Collateral dependent impaired loans $ 32,113 $ 33,567 Other real estate owned and foreclosed assets $ 358 $ 612 (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various Level 3 inputs which are not identifiable. Appraisals may be adjusted by management for qualitative factors such as economic factors and estimated liquidation expenses. The range of these possible adjustments may vary. For the fair value measurements in the table above, which are classified as Level 3 within the fair value hierarchy, the Company’s Treasury and Finance groups determine the valuation policies and procedures. For the pricing of the securities, the Company uses third-party pricing information, without adjustment. Depending on the type of the security, management employs various techniques to analyze the pricing it receives from third parties, such as analyzing changes in market yields and in certain instances reviewing the underlying collateral of the security. Management reviews changes in fair value from period to period and performs testing to ensure that prices received from the third parties are consistent with their expectation of the market. For the securities whose market is deemed to be inactive and which are categorized as Level 3, the fair value models are calibrated and significant inputs are back tested on a quarterly basis, to the extent possible. This testing is done by the third party service provider, who performs this testing by comparing anticipated inputs to actual results. Significant changes in fair value from period to period are closely scrutinized to ensure fair value models are not flawed. The driver(s) of the respective change in fair value and the method for forecasting the driver(s) is closely considered by management. The significant unobservable inputs used in the fair value measurement of the Company’s pooled trust preferred securities are cumulative prepayment rates, cumulative default rates, loss given default rates and cure given default rates. Significant increases (decreases) in deferrals or defaults, in isolation, would result in a significantly lower (higher) fair value measurement. Alternatively, significant increases (decreases) in cure rates, in isolation, would result in a significantly higher (lower) fair value measurement. Additionally, the Company has certain assets which are marked to fair value on a nonrecurring basis which are categorized within Level 3. These assets include collateral dependent impaired loans and OREO. The determination of the fair value amount is derived from the use of independent third party appraisals and evaluations. Real estate appraisals are prepared by firms from a predetermined list of qualified and approved appraisers or evaluators. Upon receipt of a real estate appraisal or evaluation, the Company's Commercial Real Estate Appraisal Department will review the report for compliance with regulatory and Company standards, as well as reasonableness and acceptance of the value conclusions. Any issues or concerns regarding compliance or value conclusions will be addressed with the engaged firm and the report may be adjusted or revised. If a disagreement cannot be resolved, the Company will either address the key issues and modify the report for acceptance or reject the report and re-order a new report. Ultimately, the Company will confirm the collateral value as part of its review process. The estimated fair values and related carrying amounts for assets and liabilities for which fair value is only disclosed are shown below as of the periods indicated: Fair Value Measurements at Reporting Date Using Carrying Value Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) March 31, 2018 (Dollars in thousands) Financial assets Securities held to maturity(a) U.S. Treasury securities $ 1,005 $ 1,021 $ — $ 1,021 $ — Agency mortgage-backed securities 192,961 190,409 — 190,409 — Agency collateralized mortgage obligations 306,395 297,818 — 297,818 — Single issuer trust preferred securities issued by banks 1,500 1,521 — 1,521 — Small business administration pooled securities 27,000 26,786 — 26,786 — Loans, net of allowance for loan losses(b) 6,269,081 6,103,312 — — 6,103,312 Federal Home Loan Bank stock(c) 13,027 13,027 — 13,027 — Cash surrender value of life insurance policies(d) 152,568 152,568 — 152,568 — Financial liabilities Deposit liabilities, other than time deposits(e) $ 6,096,756 $ 6,096,756 $ — $ 6,096,756 $ — Time certificates of deposits(f) 654,755 646,819 — 646,819 — Federal Home Loan Bank borrowings(f) 53,257 52,176 — 52,176 — Customer repurchase agreements and other short-term borrowings(f) 137,914 137,914 — — 137,914 Junior subordinated debentures(g) 73,075 72,283 — 72,283 — Subordinated debentures(f) 34,693 32,429 — — 32,429 Fair Value Measurements at Reporting Date Using Carrying Value Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2017 (Dollars in thousands) Financial assets Securities held to maturity(a) U.S. Treasury securities $ 1,006 $ 1,035 $ — $ 1,035 $ — Agency mortgage-backed securities 204,768 205,823 — 205,823 — Agency collateralized mortgage obligations 262,998 258,408 — 258,408 — Single issuer trust preferred securities issued by banks 1,500 1,529 — 1,529 — Small business administration pooled securities 27,416 27,399 — 27,399 — Loans, net of allowance for loan losses(b) 6,261,343 6,116,051 — — 6,116,051 Federal Home Loan Bank stock(c) 11,597 11,597 — 11,597 — Cash surrender value of life insurance policies(d) 151,528 151,528 — 151,528 — Financial liabilities Deposit liabilities, other than time deposits(e) $ 6,084,952 $ 6,084,952 $ — $ 6,084,952 $ — Time certificates of deposits(f) 644,301 639,060 — 639,060 — Federal Home Loan Bank borrowings(f) 53,264 52,111 — 52,111 — Customer repurchase agreements and other short-term borrowings(f) 162,679 162,679 — — 162,679 Junior subordinated debentures(g) 73,073 74,680 — 74,680 — Subordinated debentures(f) 34,682 32,707 — — 32,707 (a) The fair values presented are based on quoted market prices, where available. If quoted market prices are not available, fair values are based on quoted market prices of comparable instruments and/or discounted cash flow analysis. (b) In accordance with recent accounting guidance, the fair value of loans as of March 31, 2018 was measured using the exit price valuation method, determined primarily by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities or cash flows, while incorporating liquidity and credit assumptions. Previously the fair value of loans as of December 31, 2017 was estimated solely by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities or cash flows. Additionally, this amount excludes collateral dependent impaired loans, which are deemed to be marked to fair value on a nonrecurring basis. (c) FHLB stock has no quoted market value and is carried at cost, therefore the carrying amount approximates fair value. (d) Cash surrender value of life insurance is recorded at its cash surrender value (or the amount that can be realized upon surrender of the policy), therefore carrying amount approximates fair value. (e) Fair value of demand deposits, savings and interest checking accounts and money market deposits is the amount payable on demand at the reporting date. (f) Fair value was determined by discounting anticipated future cash payments using rates currently available for instruments with similar remaining maturities. (g) Fair value was determined based upon market prices of securities with similar terms and maturities. This summary excludes certain financial assets and liabilities for which the carrying value approximates fair value. For financial assets, these may include cash and due from banks, federal funds sold and short-term investments. For financial liabilities, these may include federal funds purchased. These instruments would all be considered to be classified as Level 1 within the fair value hierarchy. Also excluded from the summary are financial instruments measured at fair value on a recurring and nonrecurring basis, as previously described. The Company considers its current use of financial instruments to be the highest and best use of the instruments.

Revenue Recognition (Notes)

Revenue Recognition (Notes)	3 Months Ended
	Mar. 31, 2018
Revenue Recognition [Abstract]
Revenue from Contract with Customer [Text Block]	REVENUE RECOGNITION The Company adopted the new revenue recognition standard as of January 1, 2018 and is using the modified retrospective transition method upon adoption. The Company determined that there were no material changes to be made to revenue recognition upon adoption and that there were no practical expedients to apply to its contracts. A portion of the Company's noninterest income is derived from contracts with customers, and as such, the revenue recognized depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The Company considers the terms of the contract and all relevant facts and circumstances when applying this guidance. To ensure its alignment with this core principle, the Company measures revenue and the timing of recognition by applying the following five steps: 1. Identify the contract(s) with customers 2. Identify the performance obligations 3. Determine the transaction price 4. Allocate the transaction price to the performance obligations 5. Recognize revenue when (or as) the entity satisfies a performance obligation The Company has disaggregated its revenue from contracts with customers into categories that depict how the nature, amount, timing, and uncertainty of revenue and cash flows are affected by economic factors. The following table presents the revenue streams that the Company has disaggregated as of the periods indicated: Three Months Ended March 31, 2018 March 31, 2017 (Dollars in thousands) Deposit account fees (inclusive of cash management fees) $ 4,431 $ 4,544 Interchange fees 3,405 3,121 ATM fees 654 687 Investment management - wealth management and advisory services 5,582 5,137 Investment management - retail investments and insurance revenue 560 477 Merchant processing income 431 293 Other noninterest income 974 822 In each of the revenue streams identified above, there were no significant judgments made in determining or allocating the transaction price, as the consideration and service requirements are generally explicitly identified in the associated contracts. Additional information related to each of the revenue streams is further noted below: Deposit Account Fees The Company offers various deposit account products to its customers governed by specific deposit agreements applicable to either personal customers or business customers. These agreements identify the general conditions and obligations of both parties, and include standard information regarding deposit account related fees. Deposit account services include providing access to deposit accounts as well as access to the various deposit transactional services of the Company. These transactional services are primarily those that are identified in the standard fee schedule, and include, but are not limited to, services such as overdraft protection, wire transfer, and check collection. Revenue is recognized in conjunction with the various services being provided. For example, the Company may assess monthly fixed service fees associated with the customer having access to the deposit account, which can vary depending on the account type and daily account balance. In addition, the Company may also assess separate fixed fees associated with and at the time specific transactions are entered in to by the customer. As such, the Company considers its performance obligations to be met concurrently with providing the account access or completing the requested deposit transaction. Cash Management Cash management services are a subset of the Deposit account fees revenue stream. These services primarily include ACH transaction processing, positive pay and remote deposit services. These services are also governed by separate agreements entered into with the customer. The fee arrangement for these services are structured to assess fees under one of two scenarios, either a per transaction fee arrangement or an earnings credit analysis arrangement. Under the per transaction fee arrangement, fixed fees are assessed concurrently with customers executing the transactions, and as such, the Company considers its performance obligations to be met concurrently with completing the requested transaction. Under the earnings credit analysis arrangement, the Company provides a monthly earnings credit to the customer that is negotiated and determined based on various factors. The credit is then available to absorb the per transaction fees that are assessed on the customer's deposit account activity for the month. Any amount of the transactional fees in excess of the earnings credit is recognized as revenue in that month. Interchange Fees The Company earns interchange revenue from its issuance of credit and debit cards granted through its membership in various card payment networks. The Company provides credit cards and debit cards to its customers which are authorized and settled through these payment networks, and in exchange, the Company earns revenue as determined by each payment network's interchange program. The revenue is recognized concurrently with the settlement of card transactions within each network. ATM Fees The Company deploys automated teller machines (ATMs) as part of its overall branch network. Certain transactions performed at the ATMs require customers to acknowledge and pay a fee for the requested service. Certain ATM fees are disclosed in the deposit account agreement fee schedules, whereas those assessed to non-Rockland Trust deposit holders are solely determined during the transaction at the machine. The ATM fee is a fixed dollar per transaction amount, and as such, is recognized concurrently with the overall daily processing and settlement of the ATM activity. Investment Management - Wealth Management and Advisory Services The Company offers investment management and trust services to individuals, institutions, small businesses and charitable institutions. Each investment management product is governed by its own contract along with a separate identifiable fee schedule unique to that product. The Company also offers additional services, such as estate settlement, financial planning, tax services and other special services quoted at the client's request. The asset management and/or custody fees are based upon a percentage of the monthly valuation of the principal assets in the customer's account, whereas fees for additional or special services are fixed in nature and are charged as services are rendered. As the fees are dependent on assets under management, which are susceptible to market factors outside of the Company's control, this variable consideration is constrained and therefore no revenue is estimated at contract initiation. As such, all revenue is recognized in correlation to the monthly management fee determinations or as transactional services are provided. Due to the fact that payments are primarily made subsequent to the valuation period, the Company records a receivable for revenue earned but not received. The following table provides the amount of investment management revenue earned but not received as of the periods indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Receivables, included in other assets $ 1,839 $ 1,934 Investment Management - Retail Investments and Insurance Revenue The Company offers the sale of mutual fund shares, unit investment trust shares, general securities, fixed and variable annuities and life insurance products through registered representatives who are both employed by the Company and licensed and contracted with various Broker General Agents to offer these products to the Company’s customer base. As such, the Company performs these services as an agent and earns a fixed commission on the sales of these products and services. To a lesser degree, production bonus commissions can also be earned based upon the Company meeting certain volume thresholds. In general, the Company recognizes commission revenue at the point of sale, and for certain insurance products, may also earn and recognize annual residual commissions commensurate with annual premiums being paid. Merchant Processing Income The Company refers customers to third party merchant processing partners in exchange for commission and fee income. The income earned is comprised of multiple components, including a fixed referral fee per each referred customer, a rebate amount determined primarily as a percentage of net revenue earned by the third party from services provided to each referred customer, and overall production bonus commissions if certain new account production thresholds are met. Merchant processing income is recognized in conjunction with either completing the referral to earn the fixed fee amount or as the merchant activity is processed to derive the Company's rebate and/or production bonus amounts. Other Noninterest Income The Company earns various types of other noninterest income that fall within the scope of the new revenue recognition rules, and have been aggregated into one general revenue stream in the table noted above. This amount includes, but is not limited to, the following types of revenue with customers: Safe Deposit Rent The Company rents out the use of safe deposit boxes to its customers, which can be accessed when the bank is open for business. The safe deposit box rental fee is paid upfront and is recognized as revenue ratably over the annual term of the contract. 1031 Exchange Fee Revenue The Company provides like-kind exchange services pursuant to Section 1031 of the Internal Revenue Code. Fee income is recognized in conjunction with completing the exchange transactions. Foreign Currency The Company earns fee income associated with various transactions related to foreign currency product offerings, including foreign currency bank notes and drafts and foreign currency wires. The majority of this income is derived from commissions earned related to customers executing the above mentioned foreign currency transactions through arrangements with third party correspondents.

Comprehensive Income_Loss

Comprehensive Income/Loss	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
COMPREHENSIVE INCOME/LOSS	COMPREHENSIVE INCOME (LOSS) The following tables present a reconciliation of the changes in the components of other comprehensive income (loss) for the dates indicated, including the amount of income tax (expense) benefit allocated to each component of other comprehensive income (loss): Three Months Ended Pre Tax Tax (Expense) After Tax (Dollars in thousands) Change in fair value of securities available for sale $ (7,240 ) $ 1,772 $ (5,468 ) Less: net security gains reclassified into other noninterest income (expense) — — — Net change in fair value of securities available for sale (7,240 ) 1,772 (5,468 ) Change in fair value of cash flow hedges 386 (106 ) 280 Less: net cash flow hedge gains reclassified into interest income or interest expense (1) 90 (25 ) 65 Net change in fair value of cash flow hedges 296 (81 ) 215 Net unamortized loss related to defined benefit pension and other postretirement adjustments arising during the period — — — Amortization of net actuarial losses 94 (26 ) 68 Amortization of net prior service costs 69 (20 ) 49 Net change in other comprehensive income for defined benefit postretirement plans (2) 163 (46 ) 117 Total other comprehensive loss $ (6,781 ) $ 1,645 $ (5,136 ) Three Months Ended Pre Tax Tax (Expense) After Tax (Dollars in thousands) Change in fair value of securities available for sale $ 896 $ (364 ) $ 532 Less: net security losses reclassified into other noninterest income 1 — 1 Net change in fair value of securities available for sale 895 (364 ) 531 Change in fair value of cash flow hedges 58 (24 ) 34 Less: net cash flow hedge losses reclassified into interest income or interest expense (1) (93 ) 38 (55 ) Net change in fair value of cash flow hedges 151 (62 ) 89 Net unamortized loss related to defined benefit pension and other postretirement adjustments arising during the period (7 ) 3 (4 ) Amortization of net actuarial losses 70 (29 ) 41 Amortization of net prior service credits 69 (28 ) 41 Net change in other comprehensive income for defined benefit postretirement plans (2) 132 (54 ) 78 Total other comprehensive income $ 1,178 $ (480 ) $ 698 (1) Includes the amortization of the remaining balance of a realized but unrecognized gain, net of tax, from the termination of interest rate swaps in 2009. The original gain of $1.4 million , net of tax, is being recognized in earnings through December 2018 , the original maturity date of the swap. The balance of this gain has amortized to $122,000 and $137,000 at March 31, 2018 and December 31, 2017 , respectively. (2) The amortization of prior service costs is included in the computation of net periodic pension cost as disclosed in the Employee Benefit Plans footnote in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 , filed with the Securities and Exchange Commission. Effective January 1, 2018, the Company elected to reclassify certain tax effects from accumulated other comprehensive income to retained earnings, related to items that were stranded in other comprehensive income as a result of the Tax Act. A description of the other income tax effects that were reclassified as a result of the Act are listed in the table below. Information on the Company’s accumulated other comprehensive income (loss), net of tax, is comprised of the following components as of the periods indicated: Unrealized Gain on Securities Unrealized Gain (Loss) on Cash Flow Hedge Deferred Gain on Hedge Transactions Defined Benefit Postretirement Plans Accumulated Other Comprehensive Loss (Dollars in thousands) 2018 Beginning balance: January 1, 2018 $ (504 ) $ 948 $ 137 $ (2,412 ) $ (1,831 ) Opening balance reclassification (111 ) 205 29 (520 ) (397 ) Cumulative effect accounting adjustment (831 ) — — — (831 ) Net change in other comprehensive income (loss) (5,468 ) 259 (44 ) 117 (5,136 ) Ending balance: March 31, 2018 $ (6,914 ) $ 1,412 $ 122 $ (2,815 ) $ (8,195 ) 2017 Beginning balance: January 1, 2017 $ 173 $ 361 $ 281 $ (2,152 ) $ (1,337 ) Net change in other comprehensive income (loss) 531 125 (36 ) 78 698 Ending balance: March 31, 2017 $ 704 $ 486 $ 245 $ (2,074 ) $ (639 )

Commitments and contingencies

Commitments and contingencies	3 Months Ended
	Mar. 31, 2018
Other Commitments [Line Items]
Commitments and Contingencies Disclosure [Text Block]	COMMITMENTS AND CONTINGENCIES Financial Instruments with Off-Balance Sheet Risk In the normal course of business, the Company enters into various transactions to meet the financing needs of its customers, which, in accordance with GAAP, are not included in its consolidated balance sheets. These transactions include commitments to extend credit and standby letters of credit, which involve, to varying degrees, elements of credit risk and interest rate risk in excess of the amounts recognized in the consolidated balance sheets. The Company minimizes its exposure to loss under these commitments by subjecting them to credit approval and monitoring procedures. The Company enters into contractual commitments to extend credit, normally with fixed expiration dates or termination clauses, at specified rates and for specific purposes. Substantially all of these commitments to extend credit are contingent upon customers maintaining specific credit standards at the time of loan funding. Standby letters of credit are written conditional commitments issued to guarantee the performance of a customer to a third party. In the event the customer does not perform in accordance with the terms of the agreement with the third party, the Company would be required to fund the commitment. The maximum potential amount of future payments the Company could be required to make is represented by the contractual amount of the commitment. If the commitment were funded, the Company would be entitled to seek recovery from the customer. The Company’s policies generally require that standby letter of credit arrangements contain security and debt covenants similar to those contained in loan agreements. The fees collected in connection with the issuance of standby letters of credit are representative of the fair value of the Company's obligation undertaken in issuing the guarantee. In accordance with applicable accounting standards related to guarantees, fees collected in connection with the issuance of standby letters of credit are deferred. The fees are then recognized in income proportionately over the life of the standby letter of credit agreement. The deferred standby letter of credit fees represent the fair value of the Company's potential obligations under the standby letter of credit guarantees. The following table summarizes the above financial instruments at the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Commitments to extend credit $ 2,502,731 $ 2,443,478 Standby letters of credit 15,994 15,534 Deferred standby letter of credit fees 114 102 Lease Commitments The Company leases office space, space for ATM locations, and certain branch locations under noncancelable operating leases. Rent expense incurred under operating leases was approximately $2.5 million and $2.0 million the three months ended March 31, 2018 and 2017 , respectively. Several of these leases have renewal options that typically range from 5 to 10 years. There has been no significant change in the future minimum lease payments payable by the Company since December 31, 2017 . See the Company's Annual Report on Form 10-K for the fiscal year ended December 31, 2017 for information regarding leases and other commitments. Other Contingencies At March 31, 2018 , Rockland Trust was involved in pending lawsuits that arose in the ordinary course of business. Management has reviewed these pending lawsuits with legal counsel and has taken into consideration the view of counsel as to their outcome. In the opinion of management, the final disposition of pending lawsuits is not expected to have a material adverse effect on the Company’s financial position or results of operations. The Bank is required to maintain certain reserve requirements of vault cash and/or deposits with the Federal Reserve Bank of Boston. There was no reserve requirement at March 31, 2018 and the reserve requirement was $35.8 million at December 31, 2017 .

Investments is Low Income Housi

Investments is Low Income Housing Tax Credits Investments in Low Income Housing Tax Credits	3 Months Ended
	Mar. 31, 2018
Equity Method Investments and Joint Ventures [Abstract]
Investments in Low Income Housing Projects [Text Block]	LOW INCOME HOUSING PROJECT INVESTMENTS The Company has invested in low income housing projects that generate Low Income Housing Tax Credits (“LIHTC”) which provide the Company with tax credits and operating loss tax benefits over a period of approximately 15 years. None of the original investment is expected to be repaid. The following table presents certain information related to the Company's investments in low income housing projects as of the dates indicated: March 31 December 31 (Dollars in thousands) Original investment value $ 47,408 $ 47,399 Current recorded investment 34,153 35,225 Unfunded liability obligation 3,332 4,536 Tax credits and benefits 5,494 (1) 5,654 Amortization of investments 4,330 (2) 4,402 (4) Net income tax benefit 1,165 (3) 1,253 (1) This amount reflects anticipated tax credits and tax benefits for the full year ended December 31, 2018 . (2) The amortization amount reduces the tax credits and benefits anticipated for the full year ended December 31, 2018 . (3) This amount represents the net tax benefit expected to be realized for the full year ended December 31, 2018 in determining the Company's effective tax rate. (4) The 2017 amount is inclusive of $466,000 related to the revaluation of Low Income Housing tax credit investments as a result of the Tax Act.

Basis of Presentation Basis of

Basis of Presentation Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Accounting Policy	Independent Bank Corp. (the “Company”) is a state chartered, federally registered bank holding company, incorporated in 1985. The Company is the sole stockholder of Rockland Trust Company (“Rockland Trust” or the “Bank”), a Massachusetts trust company chartered in 1907. All material intercompany balances and transactions have been eliminated in consolidation. Certain previously reported amounts have been reclassified to conform to the current year’s presentation. The accompanying unaudited consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for complete financial statements. In the opinion of management, all adjustments considered necessary for a fair presentation of the financial statements, primarily consisting of normal recurring adjustments, have been included. Results for the quarter ended March 31, 2018 are not necessarily indicative of the results that may be expected for the year ending December 31, 2018 or any other interim period. For further information, refer to the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 , filed with the Securities and Exchange Commission.

Securities (Tables)

Securities (Tables)	3 Months Ended
	Mar. 31, 2018
Gain (Loss) on Investments [Line Items]
Reconciliation of fair value of securities	The following table presents a summary of the amortized cost, gross unrealized gains and losses and fair value of securities available for sale and securities held to maturity for the periods indicated: March 31, 2018 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (Dollars in thousands) Available for sale securities U.S. government agency securities $ 35,478 $ — $ (535 ) $ 34,943 $ 35,475 $ 86 $ (131 ) $ 35,430 Agency mortgage-backed securities 226,111 1,266 (4,166 ) 223,211 214,934 1,897 (1,067 ) 215,764 Agency collateralized mortgage obligations 139,433 73 (4,314 ) 135,192 124,098 78 (2,164 ) 122,012 State, county, and municipal securities 2,232 22 — 2,254 2,237 37 — 2,274 Single issuer trust preferred securities issued by banks 2,002 3 — 2,005 2,012 4 — 2,016 Pooled trust preferred securities issued by banks and insurers 2,173 — (518 ) 1,655 2,179 — (539 ) 1,640 Small business administration pooled securities 47,434 — (944 ) 46,490 47,852 44 (118 ) 47,778 Equity securities — — — — 19,432 1,594 (442 ) 20,584 Total available for sale securities $ 454,863 $ 1,364 $ (10,477 ) $ 445,750 $ 448,219 $ 3,740 $ (4,461 ) $ 447,498 Held to maturity securities U.S. Treasury securities $ 1,005 $ 16 $ — $ 1,021 $ 1,006 $ 29 $ — $ 1,035 Agency mortgage-backed securities 192,961 474 (3,026 ) 190,409 204,768 1,791 (736 ) 205,823 Agency collateralized mortgage obligations 306,395 126 (8,703 ) 297,818 262,998 397 (4,987 ) 258,408 Single issuer trust preferred securities issued by banks 1,500 21 — 1,521 1,500 29 — 1,529 Small business administration pooled securities 27,000 95 (309 ) 26,786 27,416 183 (200 ) 27,399 Total held to maturity securities $ 528,861 $ 732 $ (12,038 ) $ 517,555 $ 497,688 $ 2,429 $ (5,923 ) $ 494,194 Total $ 983,724 $ 2,096 $ (22,515 ) $ 963,305 $ 945,907 $ 6,169 $ (10,384 ) $ 941,692
Schedule of contractual maturities of securities	A schedule of the contractual maturities of securities available for sale and securities held to maturity as of March 31, 2018 is presented below: Due in one year or less Due after one year to five years Due after five to ten years Due after ten years Total Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value Amortized Cost Fair Value (Dollars in thousands) Available for sale securities U.S. government agency securities $ 2,997 $ 2,995 $ 20,016 $ 19,860 $ 12,465 $ 12,088 $ — $ — $ 35,478 $ 34,943 Agency mortgage-backed securities 84 85 43,016 42,235 97,629 96,201 85,382 84,690 226,111 223,211 Agency collateralized mortgage obligations 8 8 — — — — 139,425 135,184 139,433 135,192 State, county, and municipal securities — — 1,026 1,028 1,206 1,226 — — 2,232 2,254 Single issuer trust preferred securities issued by banks — — — — — — 2,002 2,005 2,002 2,005 Pooled trust preferred securities issued by banks and insurers — — — — — — 2,173 1,655 2,173 1,655 Small business administration pooled securities — — — — — — 47,434 46,490 47,434 46,490 Total available for sale securities $ 3,089 $ 3,088 $ 64,058 $ 63,123 $ 111,300 $ 109,515 $ 276,416 $ 270,024 $ 454,863 $ 445,750 Held to maturity securities U.S. Treasury securities $ — $ — $ 1,005 $ 1,021 $ — $ — $ — $ — $ 1,005 $ 1,021 Agency mortgage-backed securities — — 9,052 8,932 14,057 14,146 169,852 167,331 192,961 190,409 Agency collateralized mortgage obligations — — — — 1,426 1,423 304,969 296,395 306,395 297,818 Single issuer trust preferred securities issued by banks — — — — — — 1,500 1,521 1,500 1,521 Small business administration pooled securities — — — — — — 27,000 26,786 27,000 26,786 Total held to maturity securities $ — $ — $ 10,057 $ 9,953 $ 15,483 $ 15,569 $ 503,321 $ 492,033 $ 528,861 $ 517,555
Schedule of gross unrealized losses and fair value of investments	The following tables show the gross unrealized losses and fair value of the Company’s investments in an unrealized loss position, which the Company has not deemed to be OTTI, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position: March 31, 2018 Less than 12 months 12 months or longer Total # of holdings Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (Dollars in thousands) U.S. government agency securities 6 $ 34,943 $ (535 ) $ — $ — $ 34,943 $ (535 ) Agency mortgage-backed securities 140 338,326 (6,624 ) 14,205 (568 ) 352,531 (7,192 ) Agency collateralized mortgage obligations 51 244,572 (5,384 ) 150,834 (7,633 ) 395,406 (13,017 ) Pooled trust preferred securities issued by banks and insurers 1 — — 1,655 (518 ) 1,655 (518 ) Small business administration pooled securities 6 56,839 (1,074 ) 9,569 (179 ) 66,408 (1,253 ) Total temporarily impaired securities 204 $ 674,680 $ (13,617 ) $ 176,263 $ (8,898 ) $ 850,943 $ (22,515 ) December 31, 2017 Less than 12 months 12 months or longer Total # of holdings Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (Dollars in thousands) U.S.government agency securities 4 $ 24,343 $ (131 ) $ — $ — $ 24,343 $ (131 ) Agency mortgage-backed securities 84 235,411 (1,493 ) 14,886 (310 ) 250,297 (1,803 ) Agency collateralized mortgage obligations 42 178,142 (1,579 ) 159,506 (5,572 ) 337,648 (7,151 ) Pooled trust preferred securities issued by banks and insurers 1 — — 1,640 (539 ) 1,640 (539 ) Small business administration pooled securities 4 34,553 (223 ) 9,647 (95 ) 44,200 (318 ) Equity securities 28 3,290 (39 ) 7,619 (403 ) 10,909 (442 ) Total temporarily impaired securities 163 $ 475,739 $ (3,465 ) $ 193,298 $ (6,919 ) $ 669,037 $ (10,384 )

Loans, Allowance for Loan Los25

Loans, Allowance for Loan Losses and Credit Quality (Tables)	3 Months Ended
	Mar. 31, 2018
Loans, Allowance for Loan Losses and Credit Quality [Abstract]
Tabular disclosure of financing receivables bifurcated by type of impairment evaluation [Table Text Block]	The following tables bifurcate the amount of loans and the allowance allocated to each loan category based on the type of impairment analysis as of the periods indicated: March 31, 2018 (Dollars in thousands) Commercial and Industrial Commercial Real Estate Commercial Construction Small Business Residential Real Estate Home Equity Other Consumer Total Financing receivables ending balance: Collectively evaluated for impairment $ 870,110 $ 3,079,910 $ 400,934 $ 132,813 $ 742,744 $ 1,044,316 $ 8,896 $ 6,279,723 Individually evaluated for impairment $ 33,104 $ 16,470 $ — $ 853 $ 13,278 $ 6,926 $ 292 $ 70,923 Purchased credit impaired loans $ — $ 5,891 $ — $ — $ 5,309 $ 210 $ — $ 11,410 Total loans by group $ 903,214 $ 3,102,271 $ 400,934 $ 133,666 $ 761,331 $ 1,051,452 $ 9,188 $ 6,362,056 (1 ) December 31, 2017 (Dollars in thousands) Commercial and Industrial Commercial Real Estate Commercial Construction Small Business Residential Real Estate Home Equity Other Consumer Total Financing receivables ending balance: Collectively evaluated for impairment $ 853,885 $ 3,093,945 $ 401,797 $ 131,667 $ 733,809 $ 1,045,053 $ 9,573 $ 6,269,729 Individually evaluated for impairment $ 34,643 $ 16,638 $ — $ 703 $ 13,684 $ 6,826 $ 307 $ 72,801 Purchased credit impaired loans $ — $ 5,978 $ — $ — $ 6,836 $ 209 $ — $ 13,023 Total loans by group $ 888,528 $ 3,116,561 $ 401,797 $ 132,370 $ 754,329 $ 1,052,088 $ 9,880 $ 6,355,553 (1 ) (1) The amount of net deferred costs on originated loans included in the ending balance was $6.4 million and $6.1 million at March 31, 2018 and December 31, 2017 , respectively. Net unamortized discounts on acquired loans not deemed to be purchased credit impaired ("PCI") included in the ending balance was $9.1 million and $9.4 million at March 31, 2018 and December 31, 2017 , respectively.
Summary of changes in allowance for loan losses	The following tables summarize changes in allowance for loan losses by loan category for the periods indicated: Three Months Ended March 31, 2018 (Dollars in thousands) Commercial and Commercial Commercial Small Residential Other Consumer Total Allowance for loan losses Beginning balance $ 13,256 $ 31,453 $ 5,698 $ 1,577 $ 2,822 $ 5,390 $ 447 $ 60,643 Charge-offs (133 ) — — (24 ) (39 ) (79 ) (318 ) (593 ) Recoveries 12 20 — 9 2 34 235 312 Provision (benefit) 398 (14 ) (19 ) 31 52 14 38 500 Ending balance $ 13,533 $ 31,459 $ 5,679 $ 1,593 $ 2,837 $ 5,359 $ 402 $ 60,862 Ending balance: collectively evaluated for impairment $ 13,524 $ 31,422 $ 5,679 $ 1,590 $ 1,893 $ 5,111 $ 386 $ 59,605 Ending balance: individually evaluated for impairment $ 9 $ 37 $ — $ 3 $ 944 $ 248 $ 16 $ 1,257 Three Months Ended March 31, 2017 (Dollars in thousands) Commercial and Industrial Commercial Real Estate Commercial Construction Small Business Residential Real Estate Home Equity Other Consumer Total Allowance for loan losses Beginning balance $ 16,921 $ 30,369 $ 4,522 $ 1,502 $ 2,621 $ 5,238 $ 393 $ 61,566 Charge-offs — — — (70 ) (23 ) (14 ) (401 ) (508 ) Recoveries 187 31 — 66 12 76 288 660 Provision (benefit) (590 ) 343 501 35 106 45 160 600 Ending balance $ 16,518 $ 30,743 $ 5,023 $ 1,533 $ 2,716 $ 5,345 $ 440 $ 62,318 Ending balance: collectively evaluated for impairment $ 12,960 $ 30,570 $ 5,023 $ 1,531 $ 1,650 $ 5,110 $ 419 $ 57,263 Ending balance: individually evaluated for impairment $ 3,558 $ 173 $ — $ 2 $ 1,066 $ 235 $ 21 $ 5,055
Internal risk-rating categories for the Company's commercial portfolio	The following tables detail the amount of outstanding principal balances relative to each of the risk-rating categories for the Company’s commercial portfolio: March 31, 2018 Category Risk Rating Commercial and Industrial Commercial Real Estate Commercial Construction Small Business Total (Dollars in thousands) Pass 1 - 6 $ 829,401 $ 2,992,497 $ 399,568 $ 131,237 $ 4,352,703 Potential weakness 7 15,910 70,879 947 1,404 89,140 Definite weakness-loss unlikely 8 51,782 38,431 419 1,022 91,654 Partial loss probable 9 6,121 464 — 3 6,588 Definite loss 10 — — — — — Total $ 903,214 $ 3,102,271 $ 400,934 $ 133,666 $ 4,540,085 December 31, 2017 Category Risk Rating Commercial and Industrial Commercial Real Estate Commercial Construction Small Business Total (Dollars in thousands) Pass 1 - 6 $ 806,331 $ 3,007,672 $ 400,964 $ 130,265 $ 4,345,232 Potential weakness 7 16,563 69,788 — 1,471 87,822 Definite weakness-loss unlikely 8 59,415 38,637 833 631 99,516 Partial loss probable 9 6,219 464 — 3 6,686 Definite loss 10 — — — — — Total $ 888,528 $ 3,116,561 $ 401,797 $ 132,370 $ 4,539,256
Weighted average FICO scores and the weighted average combined LTV ratio	The following table shows the weighted average FICO scores and the weighted average combined LTV ratios as of the periods indicated below: March 31, December 31, Residential portfolio FICO score (re-scored)(1) 747 745 LTV (re-valued)(2) 58.2 % 59.2 % Home equity portfolio FICO score (re-scored)(1) 768 766 LTV (re-valued)(2)(3) 48.7 % 50.1 % (1) The average FICO scores at March 31, 2018 are based upon rescores available from February 2018 and origination score data for loans booked in March 2018. The average FICO scores at December 31, 2017 are based upon rescores available from August 2017 and origination score data for loans booked between September and December 2017. (2) The combined LTV ratios for March 31, 2018 are based upon updated automated valuations as of February 2018, when available or the most current valuation data available. The combined LTV ratios for December 31, 2017 are based upon updated automated valuations as of August 2017, when available, or the most current valuation data available. The updated automated valuations provides new information on loans that may be available since the previous valuation was obtained. If no new information is available, the valuation will default to the previously obtained data or most recent appraisal. (3) For home equity loans and lines in a subordinate lien, the LTV data represents a combined LTV, taking into account the senior lien data for loans and lines.
Summary of nonaccrual loans	The following table shows information regarding nonaccrual loans at the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Commercial and industrial $ 30,751 $ 32,055 Commercial real estate 2,997 3,123 Small business 412 230 Residential real estate 7,646 8,129 Home equity 5,858 6,022 Other consumer 40 71 Total nonaccrual loans (1) $ 47,704 $ 49,630 (1) Included in these amounts were $5.6 million and $6.1 million of nonaccruing TDRs at March 31, 2018 and December 31, 2017 , respectively.
Foreclosed Residential Real Estate Property [Table Text Block]	The following table shows information regarding foreclosed residential real estate property at the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Foreclosed residential real estate property held by the creditor $ 358 $ 612 Recorded investment in mortgage loans collateralized by residential real estate property that are in the process of foreclosure $ 2,094 $ 2,971
Age analysis of past due financing receivables	The following tables show the age analysis of past due financing receivables as of the dates indicated: March 31, 2018 30-59 days 60-89 days 90 days or more Total Past Due Total Financing Receivables Recorded Investment >90 Days and Accruing Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Current (Dollars in thousands) Loan Portfolio Commercial and industrial 4 $ 411 2 $ 101 14 $ 30,638 20 $ 31,150 $ 872,064 $ 903,214 $ — Commercial real estate 9 3,127 4 1,253 6 1,413 19 5,793 3,096,478 3,102,271 — Commercial construction 2 855 — — — — 2 855 400,079 400,934 — Small business 11 107 8 69 23 347 42 523 133,143 133,666 — Residential real estate 13 1,834 7 1,100 19 3,052 39 5,986 755,345 761,331 — Home equity 22 2,266 8 882 26 2,440 56 5,588 1,045,864 1,051,452 — Other consumer (1) 221 104 7 2 18 20 246 126 9,062 9,188 9 Total 282 $ 8,704 36 $ 3,407 106 $ 37,910 424 $ 50,021 $ 6,312,035 $ 6,362,056 $ 9 December 31, 2017 30-59 days 60-89 days 90 days or more Total Past Due Total Financing Receivables Recorded Investment >90 Days and Accruing Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Number of Loans Principal Balance Current (Dollars in thousands) Loan Portfolio Commercial and industrial 2 $ 195 2 $ 370 14 $ 32,007 18 $ 32,572 $ 855,956 $ 888,528 $ — Commercial real estate 7 3,060 — — 9 1,793 16 4,853 3,111,708 3,116,561 — Commercial construction — — — — — — — — 401,797 401,797 — Small business 17 339 11 144 10 57 38 540 131,830 132,370 — Residential real estate 6 870 13 2,385 22 3,471 41 6,726 747,603 754,329 — Home equity 22 1,310 6 451 20 2,025 48 3,786 1,048,302 1,052,088 — Other consumer (1) 265 197 16 27 17 45 298 269 9,611 9,880 8 Total 319 $ 5,971 48 $ 3,377 92 $ 39,398 459 $ 48,746 $ 6,306,807 $ 6,355,553 $ 8 (1) Other consumer portfolio is inclusive of deposit account overdrafts recorded as loan balances.
Summary of Troubled Debt Restructuring and other pertinent information	The following table shows the Company’s total TDRs and other pertinent information as of the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) TDRs on accrual status $ 25,617 $ 25,852 TDRs on nonaccrual 5,637 6,067 Total TDRs $ 31,254 $ 31,919 Amount of specific reserves included in the allowance for loan losses associated with TDRs $ 1,257 $ 1,342 Additional commitments to lend to a borrower who has been a party to a TDR $ 600 $ 487
Change in investment recorded subsequent to modifications	The following tables show the modifications which occurred during the periods indicated and the change in the recorded investment subsequent to the modifications occurring: Three Months Ended March 31, 2018 Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment (1) (Dollars in thousands) Troubled debt restructurings Commercial real estate 1 445 445 Home equity 2 242 242 Total 3 $ 687 $ 687 Three Months Ended March 31, 2017 Number of Contracts Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment (1) (Dollars in thousands) Troubled debt restructurings Commercial and industrial 2 $ 80 $ 80 Commercial real estate 4 934 934 Small business 4 143 143 Home equity 2 140 140 Total 12 $ 1,297 $ 1,297 (1) The post-modification balances represent the legal principal balance of the loan on the date of modification. These amounts may show an increase when modifications include a capitalization of interest.
Post modification balance of Troubled Debt Restructuring	The following table shows the Company’s post-modification balance of TDRs listed by type of modification during the periods indicated: Three Months Ended March 31 2018 2017 (Dollars in thousands) Extended maturity $ 445 $ 1,207 Court ordered concession 242 90 Total $ 687 $ 1,297
Impaired loans by loan portfolio	The tables below set forth information regarding the Company’s impaired loans by loan portfolio at the dates indicated: March 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 32,878 $ 38,785 $ — Commercial real estate 14,747 15,894 — Small business 727 797 — Residential real estate 4,234 4,367 — Home equity 5,248 5,357 — Other consumer 85 86 — Subtotal 57,919 65,286 — With an allowance recorded Commercial and industrial $ 226 $ 226 $ 9 Commercial real estate 1,723 1,723 37 Small business 126 132 3 Residential real estate 9,044 9,790 944 Home equity 1,678 1,919 248 Other consumer 207 209 16 Subtotal 13,004 13,999 1,257 Total $ 70,923 $ 79,285 $ 1,257 December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 34,267 $ 38,329 $ — Commercial real estate 13,245 14,374 — Small business 556 619 — Residential real estate 4,264 4,397 — Home equity 4,950 5,056 — Other consumer 91 92 — Subtotal 57,373 62,867 — With an allowance recorded Commercial and industrial $ 376 $ 376 $ 10 Commercial real estate 3,393 3,399 42 Small business 147 153 1 Residential real estate 9,420 10,154 1,007 Home equity 1,876 2,110 265 Other consumer 216 217 17 Subtotal 15,428 16,409 1,342 Total $ 72,801 $ 79,276 $ 1,342
Interest income recognized on impaired loans	The following tables set forth information regarding interest income recognized on impaired loans, by portfolio, for the periods indicated: Three Months Ended March 31, 2018 Average Recorded Investment Interest Income Recognized (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 33,784 $ 31 Commercial real estate 14,855 157 Small business 710 5 Residential real estate 4,254 53 Home equity 5,280 53 Other consumer 87 1 Subtotal 58,970 300 With an allowance recorded Commercial and industrial $ 227 $ 2 Commercial real estate 1,730 24 Small business 131 2 Residential real estate 9,060 71 Home equity 1,688 12 Other consumer 211 2 Subtotal 13,047 113 Total $ 72,017 $ 413 Three Months Ended March 31, 2017 Average Recorded Investment Interest Income Recognized (Dollars in thousands) With no related allowance recorded Commercial and industrial $ 39,193 $ 208 Commercial real estate 9,678 91 Small business 304 3 Residential real estate 3,671 43 Home equity 4,323 44 Other consumer 120 2 Subtotal 57,289 391 With an allowance recorded Commercial and industrial $ 10,178 $ 4 Commercial real estate 5,189 50 Small business 457 5 Residential real estate 10,057 85 Home equity 1,402 13 Other consumer 245 2 Subtotal 27,528 159 Total $ 84,817 $ 550
Certain Loans Acquired In Transfer Accounted For As Debt Securities Acquired During Period	The following table displays certain information pertaining to PCI loans at the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Outstanding balance $ 12,868 $ 14,485 Carrying amount $ 11,410 $ 13,023
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield Movement Schedule	The following table summarizes activity in the accretable yield for the PCI loan portfolio: Three Months Ended March 31 2018 2017 (Dollars in thousands) Beginning balance $ 1,791 $ 2,370 Accretion (215 ) (307 ) Other change in expected cash flows (1) 44 216 Reclassification from nonaccretable difference for loans which have paid off (2) 22 — Ending balance $ 1,642 $ 2,279 (1) Represents changes in cash flows expected to be collected and resulting in increased interest income as a prospective yield adjustment over the remaining life of the loan(s). (2) Results in increased interest income during the period in which the loan paid off at amount greater than originally expected.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2018
Earnings Per Share [Abstract]
Summary of earnings per share	Earnings per share consisted of the following components for the periods indicated: Three Months Ended March 31 2018 2017 (Dollars in thousands, except per share data) Net income $ 27,555 $ 20,725 Weighted Average Shares Basic shares 27,486,573 27,029,640 Effect of dilutive securities 67,381 81,283 Diluted shares 27,553,954 27,110,923 Net income per share Basic EPS $ 1.00 $ 0.77 Effect of dilutive securities — (0.01 ) Diluted EPS $ 1.00 $ 0.76
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]	The following table illustrates the options to purchase common stock or shares of performance-based restricted stock that were excluded from the calculation of diluted earnings per share because they were anti-dilutive for the periods indicated: Three Months Ended March 31 2018 2017 Stock options 143 — Performance-based restricted stock — 127

Stock Based Compensation (Table

Stock Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Restricted stock compensation footnote	During the three months ended March 31, 2018 , the Company made the following awards of restricted stock: Date Shares Granted Plan Grant Date Fair Value Per Share Vesting Period 2/15/2018 39,950 2005 Employee Stock Plan $ 71.75 Ratably over 5 years from grant date 2/27/2018 1,150 2005 Employee Stock Plan $ 72.60 Ratably over 5 years from grant date

Repurchase Agreements Repurchas

Repurchase Agreements Repurchase Agreements (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure of Repurchase Agreements [Abstract]
Schedule of Repurchase Agreements [Table Text Block]	The table below sets forth information regarding the Company’s repurchase agreements allocated by source of collateral at the dates indicated: March 31, December 31, (Dollars in thousands) Sources of collateral U.S. government agency securities $ 13,200 $ 16,867 Agency mortgage-backed securities 55,946 51,273 Agency collateralized mortgage obligations 68,768 94,539 Total customer repurchase agreements (1) $ 137,914 $ 162,679 (1) All customer repurchase agreements have an overnight and continuous maturity date.

Derivatives and Hedging Activ29

Derivatives and Hedging Activities (Tables)	3 Months Ended
	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes	The following tables reflect the Company's derivative positions for the periods indicated below for interest rate derivatives which qualify as cash flow hedges for accounting purposes: March 31, 2018 Notional Amount Trade Date Effective Date Maturity Date Receive (Variable) Index Current Rate Received Pay Fixed Swap Rate Fair Value (Dollars in thousands) $ 25,000 12/9/2008 12/10/2008 12/10/2018 3 Month LIBOR 2.07 % 2.94 % $ (118 ) 25,000 4/1/2016 1/17/2017 12/15/2021 3 Month LIBOR 2.12 % 1.36 % 1,128 25,000 4/1/2016 1/17/2017 12/15/2021 3 Month LIBOR 2.12 % 1.36 % 1,116 25,000 7/18/2017 8/15/2017 8/15/2022 3 Month LIBOR 1.87 % 1.88 % 796 Notional Amount Trade Date Effective Date Maturity Date Pay (Variable) Index Current Rate Paid Receive Fixed Swap Rate Fair Value 50,000 1/9/2018 1/16/2018 1/15/2023 1 Month LIBOR 1.78 % 2.24 % $ (678 ) Notional Amount Trade Date Effective Date Maturity Date Pay (Variable) Index Current Rate Paid Receive Fixed Swap Rate Cap - Floor Fair Value 50,000 1/9/2018 1/16/2018 1/15/2022 1 Month LIBOR 1.78 % 2.75% - 1.80% $ (270 ) $ 1,974
Summary of customer related derivative positions, not designated as hedging	The following tables reflect the Company’s customer related derivative positions for the periods indicated below for those derivatives not designated as hedging: Notional Amount Maturing Number of Positions (1) Less than 1 year Less than 2 years Less than 3 years Less than 4 years Thereafter Total Fair Value March 31, 2018 (Dollars in thousands) Loan level swaps Receive fixed, pay variable 248 $ 34,081 $ 95,894 $ 173,172 $ 59,531 $ 602,621 $ 965,299 $ (11,404 ) Pay fixed, receive variable 233 $ 34,081 $ 95,894 $ 173,172 $ 59,531 $ 602,621 $ 965,299 $ 11,390 Foreign exchange contracts Buys foreign currency, sells U.S. currency 18 $ 33,089 $ — $ — $ — $ — $ 33,089 $ 770 Buys U.S. currency, sells foreign currency 18 $ 33,089 $ — $ — $ — $ — $ 33,089 $ (751 ) December 31, 2017 (Dollars in thousands) Loan level swaps Receive fixed, pay variable 246 $ 36,023 $ 61,500 $ 152,287 $ 111,147 $ 591,385 $ 952,342 $ 3,875 Pay fixed, receive variable 231 $ 36,023 $ 61,500 $ 152,287 $ 111,147 $ 591,385 $ 952,342 $ (3,880 ) Foreign exchange contracts Buys foreign currency, sells U.S. currency 15 $ 26,382 $ 3,780 $ — $ — $ — $ 30,162 $ 1,202 Buys U.S. currency, sells foreign currency 15 $ 26,382 $ 3,780 $ — $ — $ — $ 30,162 $ (1,188 ) (1) The Company may enter into one dealer swap agreement which offsets multiple commercial borrower swap agreements.
Fair value of derivative financial instruments as well as their classification on the balance sheet	The table below presents the fair value of the Company’s derivative financial instruments, as well as their classification on the balance sheet at the periods indicated: Asset Derivatives Liability Derivatives Fair Value at Fair Value at Fair Value at Fair Value at Balance Sheet March 31 December 31 Balance Sheet March 31 December 31 (Dollars in thousands) Derivatives designated as hedges Interest rate derivatives Other assets $ 3,040 $ 1,880 Other liabilities $ 1,066 $ 264 Derivatives not designated as hedges Customer Related Positions Loan level derivatives Other assets $ 16,916 $ 14,236 Other liabilities $ 16,930 $ 14,241 Foreign exchange contracts Other assets 914 1,202 Other liabilities 895 1,188 Mortgage Derivatives Interest rate lock commitments Other assets 151 149 Other liabilities — — Forward sales agreements Other assets 19 9 Other liabilities — — $ 18,000 $ 15,596 $ 17,825 $ 15,429 Total $ 21,040 $ 17,476 $ 18,891 $ 15,693
Effect of derivative financial instruments included in OCI and current earnings	The table below presents the effect of the Company’s derivative financial instruments included in OCI and current earnings for the periods indicated: Three Months Ended March 31 2018 2017 (Dollars in thousands) Derivatives designated as hedges Gain in OCI on derivatives (effective portion), net of tax $ 215 $ 89 Gain (loss) reclassified from OCI into interest income or interest expense (effective portion) $ 90 $ (93 ) Loss recognized in income on derivatives (ineffective portion and amount excluded from effectiveness testing) Interest expense $ — $ — Other expense — — Total $ — $ — Derivatives not designated as hedges Changes in fair value of customer related positions Other income $ 9 $ (7 ) Other expense (13 ) (6 ) Changes in fair value of mortgage derivatives Mortgage banking income 12 50 Total $ 8 $ 37

Asset & Liability Derivative Po

Asset & Liability Derivative Positions & the Potential Effect of Netting Arrangements - Current Quarter (Tables)	3 Months Ended
	Mar. 31, 2018
Offsetting [Abstract]
Offsetting Assets [Table Text Block]	The following tables present the Company's asset and liability derivative positions and the potential effect of netting arrangements on its financial position, as of the periods indicated: Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts Recognized in the Statement of Financial Position Gross Amounts Offset in the Statement of Financial Position Net Amounts Presented in the Statement of Financial Position Financial Instruments (1) Collateral Pledged (Received) Net Amount March 31, 2018 (Dollars in thousands) Derivative Assets Interest rate swaps $ 3,040 $ — $ 3,040 $ 948 $ (1,128 ) $ 964 Loan level derivatives 16,916 — 16,916 2,767 (8,945 ) 5,204 Customer foreign exchange contracts 914 — 914 — — 914 $ 20,870 $ — $ 20,870 $ 3,715 $ (10,073 ) $ 7,082 Derivative Liabilities Interest rate swaps $ 1,066 $ — $ 1,066 $ 948 $ 118 $ — Loan level derivatives 16,930 — 16,930 2,767 141 14,022 Customer foreign exchange contracts 895 — 895 — — 895 $ 18,891 $ — $ 18,891 $ 3,715 $ 259 $ 14,917 Customer repurchase agreements 137,914 — 137,914 — 137,914 — (1) Reflects offsetting derivative positions with the same counterparty. Gross Amounts Not Offset in the Statement of Financial Position Gross Amounts Recognized in the Statement of Financial Position Gross Amounts Offset in the Statement of Financial Position Net Amounts Presented in the Statement of Financial Position Financial Instruments (1) Collateral Pledged (Received) Net Amount December 31, 2017 (Dollars in thousands) Derivative Assets Interest rate swaps $ 1,880 $ — $ 1,880 $ 805 $ — $ 1,075 Loan level derivatives 14,236 — 14,236 4,578 — 9,658 Customer foreign exchange contracts 1,202 — 1,202 — — 1,202 $ 17,318 $ — $ 17,318 $ 5,383 $ — $ 11,935 Derivative Liabilities Interest rate swaps $ 264 $ — $ 264 $ — $ 264 $ — Loan level derivatives 14,241 — 14,241 5,383 3,675 5,183 Customer foreign exchange contracts 1,188 — 1,188 — — 1,188 $ 15,693 $ — $ 15,693 $ 5,383 $ 3,939 $ 6,371 Customer repurchase agreements 162,679 — 162,679 — 162,679 — (1) Reflects offsetting derivative positions with the same counterparty.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2018
Fair Value Disclosures [Abstract]
Assets and liabilities measured at fair value on a recurring basis	Assets and liabilities measured at fair value on a recurring and nonrecurring basis were as follows as of the dates indicated: Fair Value Measurements at Reporting Date Using Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) March 31, 2018 (Dollars in thousands) Recurring fair value measurements Assets Trading securities $ 1,601 $ 1,601 $ — $ — Equity securities 20,075 20,075 — — Securities available for sale U.S. Government agency securities 34,943 — 34,943 — Agency mortgage-backed securities 223,211 — 223,211 — Agency collateralized mortgage obligations 135,192 — 135,192 — State, county, and municipal securities 2,254 — 2,254 — Single issuer trust preferred securities issued by banks and insurers 2,005 — 2,005 — Pooled trust preferred securities issued by banks and insurers 1,655 — — 1,655 Small business administration pooled securities 46,490 — 46,490 — Loans held for sale 3,937 — 3,937 — Derivative instruments 21,040 — 21,040 — Liabilities Derivative instruments 18,891 — 18,891 — Total recurring fair value measurements $ 473,512 $ 21,676 $ 450,181 $ 1,655 Nonrecurring fair value measurements Assets Collateral dependent impaired loans $ 32,113 $ — $ — $ 32,113 Other real estate owned and other foreclosed assets 358 — — 358 Total nonrecurring fair value measurements $ 32,471 $ — $ — $ 32,471 Fair Value Measurements at Reporting Date Using Balance Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2017 (Dollars in thousands) Recurring fair value measurements Assets Trading securities $ 1,324 $ 1,324 $ — $ — Equity securities 20,584 20,584 — — Securities available for sale U.S. Government agency securities 35,430 — 35,430 — Agency mortgage-backed securities 215,764 — 215,764 — Agency collateralized mortgage obligations 122,012 — 122,012 — State, county, and municipal securities 2,274 — 2,274 — Single issuer trust preferred securities issued by banks and insurers 2,016 — 2,016 — Pooled trust preferred securities issued by banks and insurers 1,640 — — 1,640 Small business administration pooled securities 47,778 — 47,778 — Loans held for sale 4,768 — 4,768 — Derivative instruments 17,476 — 17,476 — Liabilities Derivative instruments 15,693 — 15,693 — Total recurring fair value measurements $ 455,373 $ 21,908 $ 431,825 $ 1,640 Nonrecurring fair value measurements: Assets Collateral dependent impaired loans $ 33,567 $ — $ — $ 33,567 Other real estate owned and other foreclosed assets 612 — — 612 Total nonrecurring fair value measurements $ 34,179 $ — $ — $ 34,179
Reconciliation for all assets and liabilities measured at fair value on a recurring basis	The table below presents a reconciliation for all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3), which were valued using pricing models and discounted cash flow methodologies, as of the dates indicated: Three Months Ended March 31 2018 2017 (Dollars in thousands) Pooled Trust Preferred Securities Beginning balance $ 1,640 $ 1,584 Gains and (losses) (realized/unrealized) Included in other comprehensive income 21 11 Settlements (6 ) 1 Ending balance $ 1,655 $ 1,596
Investments in securities that are classified as level 3	The following table sets forth certain unobservable inputs regarding the Company’s investment in securities that are classified as Level 3 for the periods indicated: March 31 December 31 March 31 December 31 March 31 December 31 Valuation Technique Fair Value Unobservable Inputs Range Weighted Average (Dollars in thousands) Discounted cash flow methodology Pooled trust preferred securities $ 1,655 $ 1,640 Cumulative prepayment 0% - 60% 0% - 61% 2.4% 2.5% Cumulative default 5% - 100% 5% - 100% 12.3% 12.4% Loss given default 85% - 100% 85% - 100% 94.4% 94.3% Cure given default 0% - 75% 0% - 75% 60.9% 60.9% Appraisals of collateral(1) Collateral dependent impaired loans $ 32,113 $ 33,567 Other real estate owned and foreclosed assets $ 358 $ 612 (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various Level 3 inputs which are not identifiable. Appraisals may be adjusted by management for qualitative factors such as economic factors and estimated liquidation expenses. The range of these possible adjustments may vary.
The estimated fair values and related carrying amounts for assets and liabilities	The estimated fair values and related carrying amounts for assets and liabilities for which fair value is only disclosed are shown below as of the periods indicated: Fair Value Measurements at Reporting Date Using Carrying Value Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) March 31, 2018 (Dollars in thousands) Financial assets Securities held to maturity(a) U.S. Treasury securities $ 1,005 $ 1,021 $ — $ 1,021 $ — Agency mortgage-backed securities 192,961 190,409 — 190,409 — Agency collateralized mortgage obligations 306,395 297,818 — 297,818 — Single issuer trust preferred securities issued by banks 1,500 1,521 — 1,521 — Small business administration pooled securities 27,000 26,786 — 26,786 — Loans, net of allowance for loan losses(b) 6,269,081 6,103,312 — — 6,103,312 Federal Home Loan Bank stock(c) 13,027 13,027 — 13,027 — Cash surrender value of life insurance policies(d) 152,568 152,568 — 152,568 — Financial liabilities Deposit liabilities, other than time deposits(e) $ 6,096,756 $ 6,096,756 $ — $ 6,096,756 $ — Time certificates of deposits(f) 654,755 646,819 — 646,819 — Federal Home Loan Bank borrowings(f) 53,257 52,176 — 52,176 — Customer repurchase agreements and other short-term borrowings(f) 137,914 137,914 — — 137,914 Junior subordinated debentures(g) 73,075 72,283 — 72,283 — Subordinated debentures(f) 34,693 32,429 — — 32,429 Fair Value Measurements at Reporting Date Using Carrying Value Fair Value Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) December 31, 2017 (Dollars in thousands) Financial assets Securities held to maturity(a) U.S. Treasury securities $ 1,006 $ 1,035 $ — $ 1,035 $ — Agency mortgage-backed securities 204,768 205,823 — 205,823 — Agency collateralized mortgage obligations 262,998 258,408 — 258,408 — Single issuer trust preferred securities issued by banks 1,500 1,529 — 1,529 — Small business administration pooled securities 27,416 27,399 — 27,399 — Loans, net of allowance for loan losses(b) 6,261,343 6,116,051 — — 6,116,051 Federal Home Loan Bank stock(c) 11,597 11,597 — 11,597 — Cash surrender value of life insurance policies(d) 151,528 151,528 — 151,528 — Financial liabilities Deposit liabilities, other than time deposits(e) $ 6,084,952 $ 6,084,952 $ — $ 6,084,952 $ — Time certificates of deposits(f) 644,301 639,060 — 639,060 — Federal Home Loan Bank borrowings(f) 53,264 52,111 — 52,111 — Customer repurchase agreements and other short-term borrowings(f) 162,679 162,679 — — 162,679 Junior subordinated debentures(g) 73,073 74,680 — 74,680 — Subordinated debentures(f) 34,682 32,707 — — 32,707 (a) The fair values presented are based on quoted market prices, where available. If quoted market prices are not available, fair values are based on quoted market prices of comparable instruments and/or discounted cash flow analysis. (b) In accordance with recent accounting guidance, the fair value of loans as of March 31, 2018 was measured using the exit price valuation method, determined primarily by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities or cash flows, while incorporating liquidity and credit assumptions. Previously the fair value of loans as of December 31, 2017 was estimated solely by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities or cash flows. Additionally, this amount excludes collateral dependent impaired loans, which are deemed to be marked to fair value on a nonrecurring basis. (c) FHLB stock has no quoted market value and is carried at cost, therefore the carrying amount approximates fair value. (d) Cash surrender value of life insurance is recorded at its cash surrender value (or the amount that can be realized upon surrender of the policy), therefore carrying amount approximates fair value. (e) Fair value of demand deposits, savings and interest checking accounts and money market deposits is the amount payable on demand at the reporting date. (f) Fair value was determined by discounting anticipated future cash payments using rates currently available for instruments with similar remaining maturities. (g) Fair value was determined based upon market prices of securities with similar terms and maturities.

Revenue Recognition Revenue (Ta

Revenue Recognition Revenue (Tables)	3 Months Ended
	Mar. 31, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue [Table Text Block]	The following table presents the revenue streams that the Company has disaggregated as of the periods indicated: Three Months Ended March 31, 2018 March 31, 2017 (Dollars in thousands) Deposit account fees (inclusive of cash management fees) $ 4,431 $ 4,544 Interchange fees 3,405 3,121 ATM fees 654 687 Investment management - wealth management and advisory services 5,582 5,137 Investment management - retail investments and insurance revenue 560 477 Merchant processing income 431 293 Other noninterest income 974 822
Contract with Customer, Asset and Liability [Table Text Block]	The following table provides the amount of investment management revenue earned but not received as of the periods indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Receivables, included in other assets $ 1,839 $ 1,934

Comprehensive Income_Loss (Tabl

Comprehensive Income/Loss (Tables)	3 Months Ended
	Mar. 31, 2018
Equity [Abstract]
Comprehensive income	The following tables present a reconciliation of the changes in the components of other comprehensive income (loss) for the dates indicated, including the amount of income tax (expense) benefit allocated to each component of other comprehensive income (loss): Three Months Ended Pre Tax Tax (Expense) After Tax (Dollars in thousands) Change in fair value of securities available for sale $ (7,240 ) $ 1,772 $ (5,468 ) Less: net security gains reclassified into other noninterest income (expense) — — — Net change in fair value of securities available for sale (7,240 ) 1,772 (5,468 ) Change in fair value of cash flow hedges 386 (106 ) 280 Less: net cash flow hedge gains reclassified into interest income or interest expense (1) 90 (25 ) 65 Net change in fair value of cash flow hedges 296 (81 ) 215 Net unamortized loss related to defined benefit pension and other postretirement adjustments arising during the period — — — Amortization of net actuarial losses 94 (26 ) 68 Amortization of net prior service costs 69 (20 ) 49 Net change in other comprehensive income for defined benefit postretirement plans (2) 163 (46 ) 117 Total other comprehensive loss $ (6,781 ) $ 1,645 $ (5,136 ) Three Months Ended Pre Tax Tax (Expense) After Tax (Dollars in thousands) Change in fair value of securities available for sale $ 896 $ (364 ) $ 532 Less: net security losses reclassified into other noninterest income 1 — 1 Net change in fair value of securities available for sale 895 (364 ) 531 Change in fair value of cash flow hedges 58 (24 ) 34 Less: net cash flow hedge losses reclassified into interest income or interest expense (1) (93 ) 38 (55 ) Net change in fair value of cash flow hedges 151 (62 ) 89 Net unamortized loss related to defined benefit pension and other postretirement adjustments arising during the period (7 ) 3 (4 ) Amortization of net actuarial losses 70 (29 ) 41 Amortization of net prior service credits 69 (28 ) 41 Net change in other comprehensive income for defined benefit postretirement plans (2) 132 (54 ) 78 Total other comprehensive income $ 1,178 $ (480 ) $ 698 (1) Includes the amortization of the remaining balance of a realized but unrecognized gain, net of tax, from the termination of interest rate swaps in 2009. The original gain of $1.4 million , net of tax, is being recognized in earnings through December 2018 , the original maturity date of the swap. The balance of this gain has amortized to $122,000 and $137,000 at March 31, 2018 and December 31, 2017 , respectively. (2) The amortization of prior service costs is included in the computation of net periodic pension cost as disclosed in the Employee Benefit Plans footnote in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 , filed with the Securities and Exchange Commission.
Company's accumulated other comprehensive loss, net of tax	Information on the Company’s accumulated other comprehensive income (loss), net of tax, is comprised of the following components as of the periods indicated: Unrealized Gain on Securities Unrealized Gain (Loss) on Cash Flow Hedge Deferred Gain on Hedge Transactions Defined Benefit Postretirement Plans Accumulated Other Comprehensive Loss (Dollars in thousands) 2018 Beginning balance: January 1, 2018 $ (504 ) $ 948 $ 137 $ (2,412 ) $ (1,831 ) Opening balance reclassification (111 ) 205 29 (520 ) (397 ) Cumulative effect accounting adjustment (831 ) — — — (831 ) Net change in other comprehensive income (loss) (5,468 ) 259 (44 ) 117 (5,136 ) Ending balance: March 31, 2018 $ (6,914 ) $ 1,412 $ 122 $ (2,815 ) $ (8,195 ) 2017 Beginning balance: January 1, 2017 $ 173 $ 361 $ 281 $ (2,152 ) $ (1,337 ) Net change in other comprehensive income (loss) 531 125 (36 ) 78 698 Ending balance: March 31, 2017 $ 704 $ 486 $ 245 $ (2,074 ) $ (639 )

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of Fair Value, Off-balance Sheet Risks [Table Text Block]	The following table summarizes the above financial instruments at the dates indicated: March 31, 2018 December 31, 2017 (Dollars in thousands) Commitments to extend credit $ 2,502,731 $ 2,443,478 Standby letters of credit 15,994 15,534 Deferred standby letter of credit fees 114 102

Investments is Low Income Hou35

Investments is Low Income Housing Tax Credits Investments in Low Income Housing Tax Credits (Tables)	3 Months Ended
	Mar. 31, 2018
Equity Method Investments and Joint Ventures [Abstract]
Investments in Low Income Housing Projects [Table Text Block]	The following table presents certain information related to the Company's investments in low income housing projects as of the dates indicated: March 31 December 31 (Dollars in thousands) Original investment value $ 47,408 $ 47,399 Current recorded investment 34,153 35,225 Unfunded liability obligation 3,332 4,536 Tax credits and benefits 5,494 (1) 5,654 Amortization of investments 4,330 (2) 4,402 (4) Net income tax benefit 1,165 (3) 1,253 (1) This amount reflects anticipated tax credits and tax benefits for the full year ended December 31, 2018 . (2) The amortization amount reduces the tax credits and benefits anticipated for the full year ended December 31, 2018 . (3) This amount represents the net tax benefit expected to be realized for the full year ended December 31, 2018 in determining the Company's effective tax rate. (4) The 2017 amount is inclusive of $466,000 related to the revaluation of Low Income Housing tax credit investments as a result of the Tax Act.

Securities (Reconciliation of f

Securities (Reconciliation of fair value of securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	$ 454,863	$ 448,219
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	1,364	3,740
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(10,477)	(4,461)
Available-for-sale Securities	445,750	447,498
Held to maturity Securities, Amortized Cost	528,861	497,688
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	732	2,429
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(12,038)	(5,923)
Held to Maturity, Fair Value, Total	517,555	494,194
Amortized Cost	983,724	945,907
Gross Unrealized Gains	2,096	6,169
Unrealized Losses Other	(22,515)	(10,384)
Fair Value	963,305	941,692
U. S. Government Agency Securities [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	35,478	35,475
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		86
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(535)	(131)
Available-for-sale Securities	34,943	35,430
U.S. Treasury securities
Reconciliation of fair value of securities
Held to maturity Securities, Amortized Cost	1,005	1,006
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	16	29
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held to Maturity, Fair Value, Total	1,021	1,035
Agency mortgage-backed securities
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	226,111	214,934
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	1,266	1,897
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(4,166)	(1,067)
Available-for-sale Securities	223,211	215,764
Held to maturity Securities, Amortized Cost	192,961	204,768
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	474	1,791
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(3,026)	(736)
Held to Maturity, Fair Value, Total	190,409	205,823
Agency Collateralized Mortgage Obligations [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	139,433	124,098
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	73	78
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(4,314)	(2,164)
Available-for-sale Securities	135,192	122,012
Held to maturity Securities, Amortized Cost	306,395	262,998
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	126	397
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(8,703)	(4,987)
Held to Maturity, Fair Value, Total	297,818	258,408
State, County, and Municipal Securities [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	2,232	2,237
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	22	37
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Available-for-sale Securities	2,254	2,274
Single Issuer Trust Preferred Securities Issued by Banks and Insurers [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	2,002	2,012
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	3	4
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Available-for-sale Securities	2,005	2,016
Held to maturity Securities, Amortized Cost	1,500	1,500
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	21	29
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	0	0
Held to Maturity, Fair Value, Total	1,521	1,529
Pooled trust preferred securities issued by banks and insurers
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	2,173	2,179
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(518)	(539)
Available-for-sale Securities	1,655	1,640
Small Business Administration Pooled Securities [Member]
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	47,434	47,852
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax	0	44
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	(944)	(118)
Available-for-sale Securities	46,490	47,778
Held to maturity Securities, Amortized Cost	27,000	27,416
Held-to-maturity Securities, Accumulated Unrecognized Holding Gain	95	183
Held-to-maturity Securities, Accumulated Unrecognized Holding Loss	(309)	(200)
Held to Maturity, Fair Value, Total	26,786	27,399
Equity securities
Reconciliation of fair value of securities
Available for sale Securities, Amortized Cost	0	19,432
Available-for-sale Debt Securities, Accumulated Gross Unrealized Gain, before Tax		1,594
Available-for-sale Debt Securities, Accumulated Gross Unrealized Loss, before Tax	$ 0	(442)
Available-for-sale Securities		$ 20,584

Securities (Schedule of Contrac

Securities (Schedule of Contractual Maturities of Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Available for Sale, Amortized Cost
Available for sale Securities, Amortized Cost	$ 454,863	$ 448,219
Available for Sale, Fair Value
Available for sale Securities, Fair Value, Total	445,750	447,498
Held to Maturity, Amortized Cost
Held to maturity Securities, Amortized Cost	528,861	497,688
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Total	517,555	494,194
Debt Securities
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	3,089
Available for Sale, Amortized Cost, Due after one year to five years	64,058
Available for Sale, Amortized Cost, Due after five to ten years	111,300
Available for Sale, Amortized Cost, Due after ten years	276,416
Available for sale Securities, Amortized Cost	454,863
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	3,088
Available for Sale, Fair Value, Due after one year to five years	63,123
Available for Sale, Fair Value, Due after five to ten years	109,515
Available for Sale, Fair Value, Due after ten years	270,024
Available for sale Securities, Fair Value, Total	445,750
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	10,057
Held to Maturity, Amortized Cost, Due after five to ten years	15,483
Held to Maturity, Amortized Cost, Due after ten years	503,321
Held to maturity Securities, Amortized Cost	528,861
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	9,953
Held to Maturity, Fair Value, Due after five to ten years	15,569
Held to Maturity, Fair Value, Due after ten years	492,033
Held to Maturity, Fair Value, Total	517,555
U.S. Government agency securities
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	2,997
Available for Sale, Amortized Cost, Due after one year to five years	20,016
Available for Sale, Amortized Cost, Due after five to ten years	12,465
Available for Sale, Amortized Cost, Due after ten years	0
Available for sale Securities, Amortized Cost	35,478	35,475
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	2,995
Available for Sale, Fair Value, Due after one year to five years	19,860
Available for Sale, Fair Value, Due after five to ten years	12,088
Available for Sale, Fair Value, Due after ten years	0
Available for sale Securities, Fair Value, Total	34,943	35,430
Small Business Administration Pooled Securities [Member]
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	0
Available for Sale, Amortized Cost, Due after one year to five years	0
Available for Sale, Amortized Cost, Due after five to ten years	0
Available for Sale, Amortized Cost, Due after ten years	47,434
Available for sale Securities, Amortized Cost	47,434	47,852
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	0
Available for Sale, Fair Value, Due after one year to five years	0
Available for Sale, Fair Value, Due after five to ten years	0
Available for Sale, Fair Value, Due after ten years	46,490
Available for sale Securities, Fair Value, Total	46,490	47,778
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	0
Held to Maturity, Amortized Cost, Due after five to ten years	0
Held to Maturity, Amortized Cost, Due after ten years	27,000
Held to maturity Securities, Amortized Cost	27,000	27,416
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	0
Held to Maturity, Fair Value, Due after five to ten years	0
Held to Maturity, Fair Value, Due after ten years	26,786
Held to Maturity, Fair Value, Total	26,786	27,399
Pooled trust preferred securities issued by banks and insurers
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	0
Available for Sale, Amortized Cost, Due after one year to five years	0
Available for Sale, Amortized Cost, Due after five to ten years	0
Available for Sale, Amortized Cost, Due after ten years	2,173
Available for sale Securities, Amortized Cost	2,173	2,179
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	0
Available for Sale, Fair Value, Due after one year to five years	0
Available for Sale, Fair Value, Due after five to ten years	0
Available for Sale, Fair Value, Due after ten years	1,655
Available for sale Securities, Fair Value, Total	1,655	1,640
Single Issuer Trust Preferred Securities Issued by Banks and Insurers [Member]
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	0
Available for Sale, Amortized Cost, Due after one year to five years	0
Available for Sale, Amortized Cost, Due after five to ten years	0
Available for Sale, Amortized Cost, Due after ten years	2,002
Available for sale Securities, Amortized Cost	2,002	2,012
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	0
Available for Sale, Fair Value, Due after one year to five years	0
Available for Sale, Fair Value, Due after five to ten years	0
Available for Sale, Fair Value, Due after ten years	2,005
Available for sale Securities, Fair Value, Total	2,005	2,016
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	0
Held to Maturity, Amortized Cost, Due after five to ten years	0
Held to Maturity, Amortized Cost, Due after ten years	1,500
Held to maturity Securities, Amortized Cost	1,500	1,500
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	0
Held to Maturity, Fair Value, Due after five to ten years	0
Held to Maturity, Fair Value, Due after ten years	1,521
Held to Maturity, Fair Value, Total	1,521	1,529
US States and Political Subdivisions Debt Securities [Member]
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	0
Available for Sale, Amortized Cost, Due after one year to five years	1,026
Available for Sale, Amortized Cost, Due after five to ten years	1,206
Available for Sale, Amortized Cost, Due after ten years	0
Available for sale Securities, Amortized Cost	2,232	2,237
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	0
Available for Sale, Fair Value, Due after one year to five years	1,028
Available for Sale, Fair Value, Due after five to ten years	1,226
Available for Sale, Fair Value, Due after ten years	0
Available for sale Securities, Fair Value, Total	2,254	2,274
Collateralized Debt Obligations [Member]
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	8
Available for Sale, Amortized Cost, Due after one year to five years	0
Available for Sale, Amortized Cost, Due after five to ten years	0
Available for Sale, Amortized Cost, Due after ten years	139,425
Available for sale Securities, Amortized Cost	139,433	124,098
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	8
Available for Sale, Fair Value, Due after one year to five years	0
Available for Sale, Fair Value, Due after five to ten years	0
Available for Sale, Fair Value, Due after ten years	135,184
Available for sale Securities, Fair Value, Total	135,192	122,012
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	0
Held to Maturity, Amortized Cost, Due after five to ten years	1,426
Held to Maturity, Amortized Cost, Due after ten years	304,969
Held to maturity Securities, Amortized Cost	306,395	262,998
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	0
Held to Maturity, Fair Value, Due after five to ten years	1,423
Held to Maturity, Fair Value, Due after ten years	296,395
Held to Maturity, Fair Value, Total	297,818	258,408
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available for Sale, Amortized Cost
Available for Sale, Amortized Cost, Due in one year or less	84
Available for Sale, Amortized Cost, Due after one year to five years	43,016
Available for Sale, Amortized Cost, Due after five to ten years	97,629
Available for Sale, Amortized Cost, Due after ten years	85,382
Available for sale Securities, Amortized Cost	226,111	214,934
Available for Sale, Fair Value
Available for Sale, Fair Value, Due in one year or less	85
Available for Sale, Fair Value, Due after one year to five years	42,235
Available for Sale, Fair Value, Due after five to ten years	96,201
Available for Sale, Fair Value, Due after ten years	84,690
Available for sale Securities, Fair Value, Total	223,211	215,764
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	9,052
Held to Maturity, Amortized Cost, Due after five to ten years	14,057
Held to Maturity, Amortized Cost, Due after ten years	169,852
Held to maturity Securities, Amortized Cost	192,961	204,768
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	8,932
Held to Maturity, Fair Value, Due after five to ten years	14,146
Held to Maturity, Fair Value, Due after ten years	167,331
Held to Maturity, Fair Value, Total	190,409	205,823
US Treasury Securities [Member]
Held to Maturity, Amortized Cost
Held to Maturity, Amortized Cost, Due in one year or less	0
Held to Maturity, Amortized Cost, Due after one year to five years	1,005
Held to Maturity, Amortized Cost, Due after five to ten years	0
Held to Maturity, Amortized Cost, Due after ten years	0
Held to maturity Securities, Amortized Cost	1,005	1,006
Held to Maturity, Fair Value
Held to Maturity, Fair Value, Due in one year or less	0
Held to Maturity, Fair Value, Due after one year to five years	1,021
Held to Maturity, Fair Value, Due after five to ten years	0
Held to Maturity, Fair Value, Due after ten years	0
Held to Maturity, Fair Value, Total	$ 1,021	$ 1,035

Securities (Unrealized Loss NOT

Securities (Unrealized Loss NOT deemed to be OTTI) (Details) $ in Thousands	Mar. 31, 2018USD ($)holding	Dec. 31, 2017USD ($)holding
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	204	163
Fair value, less than 12 months	$ 674,680	$ 475,739
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(13,617)	(3,465)
Fair value, 12 months or longer	176,263	193,298
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(8,898)	(6,919)
Fair value, Total	850,943	669,037
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (22,515)	$ (10,384)
U. S. Government Agency Securities [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	6	4
Fair value, less than 12 months	$ 34,943	$ 24,343
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(535)	(131)
Fair value, 12 months or longer	0	0
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months		0
Fair value, Total	34,943	24,343
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (535)	$ (131)
Agency mortgage-backed securities
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	140	84
Fair value, less than 12 months	$ 338,326	$ 235,411
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(6,624)	(1,493)
Fair value, 12 months or longer	14,205	14,886
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(568)	(310)
Fair value, Total	352,531	250,297
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (7,192)	$ (1,803)
Agency Collateralized Mortgage Obligations [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	51	42
Fair value, less than 12 months	$ 244,572	$ 178,142
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(5,384)	(1,579)
Fair value, 12 months or longer	150,834	159,506
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(7,633)	(5,572)
Fair value, Total	395,406	337,648
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (13,017)	$ (7,151)
Pooled trust preferred securities issued by banks and insurers
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	1	1
Fair value, less than 12 months	$ 0	$ 0
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	0	0
Fair value, 12 months or longer	1,655	1,640
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(518)	(539)
Fair value, Total	1,655	1,640
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (518)	$ (539)
Equity securities
Summary of gross unrealized losses and fair value of investments
No of holdings | holding		28
Fair value, less than 12 months		$ 3,290
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months		(39)
Fair value, 12 months or longer		7,619
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months		(403)
Fair value, Total		10,909
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss		$ (442)
Small Business Administration Pooled Securities [Member]
Summary of gross unrealized losses and fair value of investments
No of holdings | holding	6	4
Fair value, less than 12 months	$ 56,839	$ 34,553
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for less than 12 months	(1,074)	(223)
Fair value, 12 months or longer	9,569	9,647
Unrealized loss position for available for sale and held to maturity securities in a continuous loss position for more than 12 months	(179)	(95)
Fair value, Total	66,408	44,200
Available for Sale and Held to Maturity Securities Continuous Unrealized Loss Position Aggregate Loss	$ (1,253)	$ (318)

Securities (Details Textual) (D

Securities (Details Textual) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities	$ 445,750,000		$ 447,498,000
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net	0	$ 0
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held	0	$ 0
Securities (Textual) [Abstract]
Callable Securities in Investment Portfolio	7,400,000
Pledged Financial Instruments, Not Separately Reported, Securities	552,700,000		547,200,000
Trading	1,601,000		1,324,000
Investments in obligations of individual states, counties or municipalities which exceed 10% of equity	0		0
Trading Securities, Equity	$ 20,075,000		0
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities			$ 20,584,000

Loans, Allowance for Loan Los40

Loans, Allowance for Loan Losses and Credit Quality (Allowance Allocations) (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Allowance for loans based on collective and individual evaluation of impairment by loan category
Ending Balance: Collectively Evaluated for Impairment		$ 6,279,723	$ 6,269,729
Ending Balance: Individually Evaluated for Impairment		70,923	72,801
Financing Receivable, Net		4,540,085	4,539,256
Ending Balance: Total Loans by Group	[1]	6,362,056	6,355,553
Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Financing Receivable, Net		11,410	13,023
Commercial and Industrial [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Ending Balance: Collectively Evaluated for Impairment		870,110	853,885
Ending Balance: Individually Evaluated for Impairment		33,104	34,643
Financing Receivable, Net		903,214	888,528
Ending Balance: Total Loans by Group	[1]	903,214	888,528
Commercial and Industrial [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Financing Receivable, Net		0	0
Commercial Real Estate [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Ending Balance: Collectively Evaluated for Impairment		3,079,910	3,093,945
Ending Balance: Individually Evaluated for Impairment		16,470	16,638
Financing Receivable, Net		3,102,271	3,116,561
Ending Balance: Total Loans by Group	[1]	3,102,271	3,116,561
Commercial Real Estate [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Financing Receivable, Net		5,891	5,978
Construction Loans [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Ending Balance: Collectively Evaluated for Impairment		400,934	401,797
Ending Balance: Individually Evaluated for Impairment		0	0
Financing Receivable, Net		400,934	401,797
Ending Balance: Total Loans by Group	[1]	400,934	401,797
Construction Loans [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Financing Receivable, Net		0	0
Small Business [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Ending Balance: Collectively Evaluated for Impairment		132,813	131,667
Ending Balance: Individually Evaluated for Impairment		853	703
Financing Receivable, Net		133,666	132,370
Ending Balance: Total Loans by Group	[1]	133,666	132,370
Small Business [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Financing Receivable, Net		0	0
Residential Real Estate [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Ending Balance: Collectively Evaluated for Impairment		742,744	733,809
Ending Balance: Individually Evaluated for Impairment		13,278	13,684
Ending Balance: Total Loans by Group	[1]	761,331	754,329
Residential Real Estate [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Financing Receivable, Net		5,309	6,836
Consumer Home Equity [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Ending Balance: Collectively Evaluated for Impairment		1,044,316	1,045,053
Ending Balance: Individually Evaluated for Impairment		6,926	6,826
Ending Balance: Total Loans by Group	[1]	1,051,452	1,052,088
Consumer Home Equity [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Financing Receivable, Net		210	209
Consumer Other [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Ending Balance: Collectively Evaluated for Impairment		8,896	9,573
Ending Balance: Individually Evaluated for Impairment		292	307
Ending Balance: Total Loans by Group	[1]	9,188	9,880	[2]
Consumer Other [Member] | Receivables Acquired with Deteriorated Credit Quality [Member]
Allowance for loans based on collective and individual evaluation of impairment by loan category
Financing Receivable, Net		$ 0	$ 0
[1]	The amount of net deferred costs on originated loans included in the ending balance was $6.4 million and $6.1 million at March 31, 2018 and December 31, 2017, respectively. Net unamortized discounts on acquired loans not deemed to be purchased credit impaired ("PCI") included in the ending balance was $9.1 million and $9.4 million at March 31, 2018 and December 31, 2017, respectively.
[2]	(1) Other consumer portfolio is inclusive of deposit account overdrafts recorded as loan balances.

Loans, Allowance for Loan Los41

Loans, Allowance for Loan Losses and Credit Quality (ALLL - by category) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Summary of changes in allowance for loan losses
Beginning Balance	$ 60,643	$ 61,566
Charge-offs	(593)	(508)
Recoveries	312	660
Provision for loan losses	500	600
Ending Balance	60,862	62,318
Ending Balance: Individually Evaluated for Impairment	1,257	5,055	$ 1,342
Ending Balance: Collectively Evaluated for Impairment	59,605	57,263
Commercial and Industrial [Member]
Summary of changes in allowance for loan losses
Beginning Balance	13,256	16,921
Charge-offs	(133)	0
Recoveries	12	187
Provision for loan losses	398	(590)
Ending Balance	13,533	16,518
Ending Balance: Individually Evaluated for Impairment	9	3,558	10
Ending Balance: Collectively Evaluated for Impairment	13,524	12,960
Commercial Real Estate [Member]
Summary of changes in allowance for loan losses
Beginning Balance	31,453	30,369
Charge-offs	0	0
Recoveries	20	31
Provision for loan losses	(14)	343
Ending Balance	31,459	30,743
Ending Balance: Individually Evaluated for Impairment	37	173	42
Ending Balance: Collectively Evaluated for Impairment	31,422	30,570
Construction Loans [Member]
Summary of changes in allowance for loan losses
Beginning Balance	5,698	4,522
Charge-offs	0	0
Recoveries	0	0
Provision for loan losses	(19)	501
Ending Balance	5,679	5,023
Ending Balance: Individually Evaluated for Impairment	0	0
Ending Balance: Collectively Evaluated for Impairment	5,679	5,023
Small Business [Member]
Summary of changes in allowance for loan losses
Beginning Balance	1,577	1,502
Charge-offs	(24)	(70)
Recoveries	9	66
Provision for loan losses	31	35
Ending Balance	1,593	1,533
Ending Balance: Individually Evaluated for Impairment	3	2	1
Ending Balance: Collectively Evaluated for Impairment	1,590	1,531
Residential Real Estate [Member]
Summary of changes in allowance for loan losses
Beginning Balance	2,822	2,621
Charge-offs	(39)	(23)
Recoveries	2	12
Provision for loan losses	52	106
Ending Balance	2,837	2,716
Ending Balance: Individually Evaluated for Impairment	944	1,066	1,007
Ending Balance: Collectively Evaluated for Impairment	1,893	1,650
Consumer Home Equity [Member]
Summary of changes in allowance for loan losses
Beginning Balance	5,390	5,238
Charge-offs	(79)	(14)
Recoveries	34	76
Provision for loan losses	14	45
Ending Balance	5,359	5,345
Ending Balance: Individually Evaluated for Impairment	248	235	265
Ending Balance: Collectively Evaluated for Impairment	5,111	5,110
Consumer Other [Member]
Summary of changes in allowance for loan losses
Beginning Balance	447	393
Charge-offs	(318)	(401)
Recoveries	235	288
Provision for loan losses	38	160
Ending Balance	402	440
Ending Balance: Individually Evaluated for Impairment	16	21	$ 17
Ending Balance: Collectively Evaluated for Impairment	$ 386	$ 419

Loans, Allowance for Loan Los42

Loans, Allowance for Loan Losses and Credit Quality (Internal Risk-Rating Categories for the Commercial Portfolio) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Significant Advanced Considered For Risk Rating Change	$ 50,000
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	4,540,085,000	$ 4,539,256,000
Commercial and Industrial [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	903,214,000	888,528,000
Commercial Real Estate [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	3,102,271,000	3,116,561,000
Commercial Construction [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	400,934,000	401,797,000
Small Business [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	133,666,000	132,370,000
PASS [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	4,352,703,000	4,345,232,000
PASS [Member] | Commercial and Industrial [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	829,401,000	806,331,000
PASS [Member] | Commercial Real Estate [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	2,992,497,000	3,007,672,000
PASS [Member] | Commercial Construction [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	399,568,000	400,964,000
PASS [Member] | Small Business [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	131,237,000	130,265,000
POTENTIAL WEAKNESS [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	89,140,000	87,822,000
POTENTIAL WEAKNESS [Member] | Commercial and Industrial [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	15,910,000	16,563,000
POTENTIAL WEAKNESS [Member] | Commercial Real Estate [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	70,879,000	69,788,000
POTENTIAL WEAKNESS [Member] | Commercial Construction [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	947,000	0
POTENTIAL WEAKNESS [Member] | Small Business [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	1,404,000	1,471,000
DEFINITE WEAKNESS-LOSS UNLIKELY [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	91,654,000	99,516,000
DEFINITE WEAKNESS-LOSS UNLIKELY [Member] | Commercial and Industrial [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	51,782,000	59,415,000
DEFINITE WEAKNESS-LOSS UNLIKELY [Member] | Commercial Real Estate [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	38,431,000	38,637,000
DEFINITE WEAKNESS-LOSS UNLIKELY [Member] | Commercial Construction [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	419,000	833,000
DEFINITE WEAKNESS-LOSS UNLIKELY [Member] | Small Business [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	1,022,000	631,000
PARTIAL LOSS PROBABLE [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	6,588,000	6,686,000
PARTIAL LOSS PROBABLE [Member] | Commercial and Industrial [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	6,121,000	6,219,000
PARTIAL LOSS PROBABLE [Member] | Commercial Real Estate [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	464,000	464,000
PARTIAL LOSS PROBABLE [Member] | Commercial Construction [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	0	0
PARTIAL LOSS PROBABLE [Member] | Small Business [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	3,000	3,000
DEFINITE LOSS [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	0	0
DEFINITE LOSS [Member] | Commercial and Industrial [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	0	0
DEFINITE LOSS [Member] | Commercial Real Estate [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	0	0
DEFINITE LOSS [Member] | Commercial Construction [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	0	0
DEFINITE LOSS [Member] | Small Business [Member]
Internal risk-rating categories for the Company's commercial portfolio
TOTAL	$ 0	$ 0

Loans, Allowance for Loan Los43

Loans, Allowance for Loan Losses and Credit Quality (Weighted Average FICO Scores and the Weighted Average Combined LTV Ratio) (Details) - score		Mar. 31, 2018	Dec. 31, 2017
Residential Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable With Quality Of Loan Based On Weighted Average Fico Rating	[1]	747	745
Financing Receivable With Credit Quality Of Loan Based Upon the Weighted Average Loan-To-Value Ratio	[2]	58.20%	59.20%
Consumer Home Equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable With Quality Of Loan Based On Weighted Average Fico Rating	[1]	768	766
Financing Receivable With Credit Quality Of Loan Based Upon the Weighted Average Loan-To-Value Ratio	[2],[3]	48.70%	50.10%
[1]	The average FICO scores at March 31, 2018 are based upon rescores available from February 2018 and origination score data for loans booked in March 2018. The average FICO scores at December 31, 2017 are based upon rescores available from August 2017 and origination score data for loans booked between September and December 2017.
[2]	The combined LTV ratios for March 31, 2018 are based upon updated automated valuations as of February 2018, when available or the most current valuation data available. The combined LTV ratios for December 31, 2017 are based upon updated automated valuations as of August 2017, when available, or the most current valuation data available. The updated automated valuations provides new information on loans that may be available since the previous valuation was obtained. If no new information is available, the valuation will default to the previously obtained data or most recent appraisal.
[3]	For home equity loans and lines in a subordinate lien, the LTV data represents a combined LTV, taking into account the senior lien data for loans and lines.

Loans, Allowance for Loan Los44

Loans, Allowance for Loan Losses and Credit Quality (Summary of Nonaccrual Loans) (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Financing Receivable Impaired [Line Items]
Tdrs Recorded Investment On Nonaccrual Status		$ 5,637	$ 6,067
Financing Receivable, Recorded Investment, Nonaccrual Status	[1]	47,704	49,630
Commercial and Industrial [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		30,751	32,055
Commercial Real Estate [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		2,997	3,123
Small Business [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		412	230
Residential Real Estate [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		7,646	8,129
Consumer Home Equity [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		5,858	6,022
Consumer - Other [Member]
Financing Receivable Impaired [Line Items]
Financing Receivable, Recorded Investment, Nonaccrual Status		$ 40	$ 71
[1]	(1)Included in these amounts were $5.6 million and $6.1 million of nonaccruing TDRs at March 31, 2018 and December 31, 2017, respectively.

Loans, Allowance for Loan Los45

Loans, Allowance for Loan Losses and Credit Quality Foreclosed Residential Real Estate Property (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Foreclosed residential real estate property held by the creditor	$ 358	$ 612
Recorded investment in mortgage loans collateralized by residential real estate property that are in the process of foreclosure	$ 2,094	$ 2,971

Loans, Allowance for Loan Los46

Loans, Allowance for Loan Losses and Credit Quality (Age Analysis of Past Due Financing Receivables) (Details) $ in Thousands		Mar. 31, 2018USD ($)loan	Dec. 31, 2017USD ($)loan
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan		282	319
Number of Loans 60-89 Days | loan		36	48
Number of Loans 90 Days or More | loan		106	92
Number of Loans Total Past Due | loan		424	459
Principal Balance Total Past Due		$ 50,021	$ 48,746
Current		6,312,035	6,306,807
Total loans	[1]	6,362,056	6,355,553
Recorded Investment >90 Days and Accruing		$ 9	$ 8
Commercial and Industrial [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan		4	2
Number of Loans 60-89 Days | loan		2	2
Number of Loans 90 Days or More | loan		14	14
Number of Loans Total Past Due | loan		20	18
Principal Balance Total Past Due		$ 31,150	$ 32,572
Current		872,064	855,956
Total loans	[1]	903,214	888,528
Recorded Investment >90 Days and Accruing		$ 0	$ 0
Commercial Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan		9	7
Number of Loans 60-89 Days | loan		4	0
Number of Loans 90 Days or More | loan		6	9
Number of Loans Total Past Due | loan		19	16
Principal Balance Total Past Due		$ 5,793	$ 4,853
Current		3,096,478	3,111,708
Total loans	[1]	3,102,271	3,116,561
Recorded Investment >90 Days and Accruing		$ 0	$ 0
Construction Loans [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan		2	0
Number of Loans 60-89 Days | loan		0	0
Number of Loans 90 Days or More | loan		0	0
Number of Loans Total Past Due | loan		2	0
Principal Balance Total Past Due		$ 855	$ 0
Current		400,079	401,797
Total loans	[1]	400,934	401,797
Recorded Investment >90 Days and Accruing		$ 0	$ 0
Small Business [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan		11	17
Number of Loans 60-89 Days | loan		8	11
Number of Loans 90 Days or More | loan		23	10
Number of Loans Total Past Due | loan		42	38
Principal Balance Total Past Due		$ 523	$ 540
Current		133,143	131,830
Total loans	[1]	133,666	132,370
Recorded Investment >90 Days and Accruing		$ 0	$ 0
Residential Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan		13	6
Number of Loans 60-89 Days | loan		7	13
Number of Loans 90 Days or More | loan		19	22
Number of Loans Total Past Due | loan		39	41
Principal Balance Total Past Due		$ 5,986	$ 6,726
Current		755,345	747,603
Total loans	[1]	761,331	754,329
Recorded Investment >90 Days and Accruing		$ 0	$ 0
Consumer Home Equity [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan		22	22
Number of Loans 60-89 Days | loan		8	6
Number of Loans 90 Days or More | loan		26	20
Number of Loans Total Past Due | loan		56	48
Principal Balance Total Past Due		$ 5,588	$ 3,786
Current		1,045,864	1,048,302
Total loans	[1]	1,051,452	1,052,088
Recorded Investment >90 Days and Accruing		$ 0	$ 0
Consumer - Other [Member]
Age Analysis of Past Due Financing Receivables
Number of Loans 30-59 Days | loan		221	265	[2]
Number of Loans 60-89 Days | loan		7	16	[2]
Number of Loans 90 Days or More | loan		18	17	[2]
Number of Loans Total Past Due | loan		246	298	[2]
Principal Balance Total Past Due		$ 126	$ 269	[2]
Current		9,062	9,611	[2]
Total loans	[1]	9,188	9,880	[2]
Recorded Investment >90 Days and Accruing		9	8
Financing Receivables, 30 to 59 Days Past Due [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		8,704	5,971
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial and Industrial [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		411	195
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		3,127	3,060
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction Loans [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		855	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Small Business [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		107	339
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		1,834	870
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Home Equity [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		2,266	1,310
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer - Other [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		104	197	[2]
Financing Receivables, 60 to 89 Days Past Due [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		3,407	3,377
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial and Industrial [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		101	370
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		1,253	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Construction Loans [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Small Business [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		69	144
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		1,100	2,385
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Home Equity [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		882	451
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer - Other [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		2	27	[2]
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		37,910	39,398
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial and Industrial [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		30,638	32,007
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		1,413	1,793
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction Loans [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Small Business [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		347	57
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Real Estate [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		3,052	3,471
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Home Equity [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		2,440	2,025
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer - Other [Member]
Age Analysis of Past Due Financing Receivables
Principal Balance Total Past Due		$ 20	$ 45	[2]
[1]	The amount of net deferred costs on originated loans included in the ending balance was $6.4 million and $6.1 million at March 31, 2018 and December 31, 2017, respectively. Net unamortized discounts on acquired loans not deemed to be purchased credit impaired ("PCI") included in the ending balance was $9.1 million and $9.4 million at March 31, 2018 and December 31, 2017, respectively.
[2]	(1) Other consumer portfolio is inclusive of deposit account overdrafts recorded as loan balances.

Loans, Allowance for Loan Los47

Loans, Allowance for Loan Losses and Credit Quality (TDR's and Other Pertinent Information) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Summary of Troubled Debt Restructurings and other pertinent information
TDRS ON ACCRUAL STATUS	$ 25,617	$ 25,852
TDRS ON NONACCRUAL	5,637	6,067
TOTAL TDR'S	31,254	31,919
AMOUNT OF SPECIFIC RESERVES INCLUDED IN THE ALLOWANCE FOR LOAN LOSSES ASSOCIATED WITH TDRS:	1,257	1,342
Additional Commitments To Lend To Borrower For Trouble Debt Restructuring	$ 600	$ 487

Loans, Allowance for Loan Los48

Loans, Allowance for Loan Losses and Credit Quality (Modifications which occurred during the period & change in recorded investment) (Details) $ in Thousands		3 Months Ended
		Mar. 31, 2018USD ($)contract	Mar. 31, 2017USD ($)contract
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract		3	12
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment		$ 687	$ 1,297
Financing Receivable, Modifications, Post-Modification Recorded Investment		$ 687	$ 1,297	[1]
Commercial and Industrial [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract			2
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment			$ 80
Financing Receivable, Modifications, Post-Modification Recorded Investment	[1]		$ 80
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract		1	4
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment		$ 445	$ 934
Financing Receivable, Modifications, Post-Modification Recorded Investment		$ 445	$ 934	[1]
Small Business [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract			4
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment			$ 143
Financing Receivable, Modifications, Post-Modification Recorded Investment	[1]		$ 143
Consumer Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts | contract		2	2
TROUBLED DEBT RESTRUCTURINGS:
Financing Receivable, Modifications, Pre-Modification Recorded Investment		$ 242	$ 140
Financing Receivable, Modifications, Post-Modification Recorded Investment		$ 242	$ 140	[1]
[1]	The post-modification balances represent the legal principal balance of the loan on the date of modification. These amounts may show an increase when modifications include a capitalization of interest.

Loans, Allowance for Loan Los49

Loans, Allowance for Loan Losses and Credit Quality (Post-Modification balance of TDRs Listed by Type of Modifications) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Post modification balance of Troubled Debt Restructuring
EXTENDED MATURITY	$ 445	$ 1,207
COURT ORDERED CONCESSION	242	90
TOTAL	$ 687	$ 1,297

Loans, Allowance for Loan Los50

Loans, Allowance for Loan Losses and Credit Quality (Impaired Loans by Portfolio) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	$ 1,257	$ 1,342	$ 5,055
Related Allowance	1,257	1,342
Impaired Financing Receivable, Recorded Investment, Total	70,923	72,801
Impaired Financing Receivable, Unpaid Principal Balance	79,285	79,276
WITH NO RELATED ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	57,919	57,373
Unpaid Principal Balance	65,286	62,867
Related Allowance	0	0
WITH AN ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	13,004	15,428
Unpaid Principal Balance	13,999	16,409
Commercial and Industrial [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	9	10	3,558
Commercial and Industrial [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	32,878	34,267
Unpaid Principal Balance	38,785	38,329
Related Allowance	0	0
Commercial and Industrial [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	226	376
Unpaid Principal Balance	226	376
Commercial Real Estate [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	37	42	173
Commercial Real Estate [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	14,747	13,245
Unpaid Principal Balance	15,894	14,374
Related Allowance	0	0
Commercial Real Estate [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	1,723	3,393
Unpaid Principal Balance	1,723	3,399
Construction Loans [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	0		0
Small Business [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	3	1	2
Small Business [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	727	556
Unpaid Principal Balance	797	619
Related Allowance	0	0
Small Business [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	126	147
Unpaid Principal Balance	132	153
Residential Real Estate [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	944	1,007	1,066
Residential Real Estate [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	4,234	4,264
Unpaid Principal Balance	4,367	4,397
Related Allowance	0	0
Residential Real Estate [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	9,044	9,420
Unpaid Principal Balance	9,790	10,154
Consumer Home Equity [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	248	265	235
Consumer Home Equity [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	5,248	4,950
Unpaid Principal Balance	5,357	5,056
Related Allowance	0	0
Consumer Home Equity [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	1,678	1,876
Unpaid Principal Balance	1,919	2,110
Consumer - Other [Member]
Impaired loans by loan portfolio
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	16	17	$ 21
Consumer - Other [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	85	91
Unpaid Principal Balance	86	92
Related Allowance	0	0
Consumer - Other [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Impaired loans by loan portfolio
Recorded Investment	207	216
Unpaid Principal Balance	$ 209	$ 217

Loans, Allowance for Loan Los51

Loans, Allowance for Loan Losses and Credit Quality (Int Inc. Recognized on Impaired Loans by Portfolio) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Interest income recognized on impaired loans
Average Recorded Investment	$ 72,017	$ 84,817
Interest Income Recognized	413	550
WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	58,970	57,289
Interest Income Recognized	300	391
WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	13,047	27,528
Interest Income Recognized	113	159
Commercial and Industrial [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	33,784	39,193
Interest Income Recognized	31	208
Commercial and Industrial [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	227	10,178
Interest Income Recognized	2	4
Commercial Real Estate [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	14,855	9,678
Interest Income Recognized	157	91
Commercial Real Estate [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	1,730	5,189
Interest Income Recognized	24	50
Small Business [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	710	304
Interest Income Recognized	5	3
Small Business [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	131	457
Interest Income Recognized	2	5
Residential Real Estate [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	4,254	3,671
Interest Income Recognized	53	43
Residential Real Estate [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	9,060	10,057
Interest Income Recognized	71	85
Consumer Home Equity [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	5,280	4,323
Interest Income Recognized	53	44
Consumer Home Equity [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	1,688	1,402
Interest Income Recognized	12	13
Consumer - Other [Member] | WITH NO RELATED ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	87	120
Interest Income Recognized	1	2
Consumer - Other [Member] | WITH AN ALLOWANCE RECORDED: [Member]
Interest income recognized on impaired loans
Average Recorded Investment	211	245
Interest Income Recognized	$ 2	$ 2

Loans, Allowance for Loan Los52

Loans, Allowance for Loan Losses and Credit Quality (Purchased Credit Impaired Loans - Outstanding/Carrying balances) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Outstanding balance	$ 12,868	$ 14,485
Financing Receivable, Net	4,540,085	4,539,256
Receivables Acquired with Deteriorated Credit Quality [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Financing Receivable, Net	$ 11,410	$ 13,023

Loans, Allowance for Loan Los53

Loans, Allowance for Loan Losses and Credit Quality (Activity in the Accretable Yield for PCI loans) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield, Beginning of Period		$ 1,791	$ 2,370
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion		(215)	(307)
Certainloansacquiredinatransfernotaccountedforasdebtsecuritiesaccretableyieldadjustmentchangesinexpectedcashflow	[1]	44	216
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield, Reclassifications from Nonaccretable Difference	[2]	22	0
Certain Loans Acquired in Transfer Accounted for as Debt Securities, Accretable Yield, End of Period		$ 1,642	$ 2,279
[1]	(1) Represents changes in cash flows expected to be collected and resulting in increased interest income as a prospective yield adjustment over the remaining life of the loan(s).
[2]	(2) Results in increased interest income during the period in which the loan paid off at amount greater than originally expected.

Loans, Allowance for Loan Los54

Loans, Allowance for Loan Losses and Credit Quality (Textual) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		$ 0
Unamortized Loan Commitment and Origination fees	$ 6,400,000		$ 6,100,000
Significant Advanced Considered For Risk Rating Change	$ 50,000
Days to be termed as non accrual loans	90 days
Tdrs Recorded Investment On Nonaccrual Status	$ 5,637,000		6,067,000
Unamortized Discounts or Premiums	$ 9,100,000		$ 9,400,000

Earnings Per Share (EPS Compone

Earnings Per Share (EPS Components) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Summary of earnings per share
Net income	$ 27,555	$ 20,725
Weighted Average Shares (in shares)
BASIC SHARES	27,486,573	27,029,640
EFFECT OF DILUTIVE SECURITIES	67,381	81,283
DILUTIVE SHARES	27,553,954	27,110,923
NET INCOME PER SHARE (in dollars per share)
BASIC EPS	$ 1	$ 0.77
EFFECT OF DILUTIVE SECURITIES	0	(0.01)
DILUTIVE EPS	$ 1	$ 0.76

Earnings Per Share Antidilutive

Earnings Per Share Antidilutive Securities excluded from the Computaion of Earnings Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Employee Stock Option [Member]
Stock Option [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	143	0
Performance Shares [Member]
Stock Option [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	127

Stock Based Compensation (Award

Stock Based Compensation (Awards of Restricted Stock) (Details) - Ratably Over Period [Member] - Employee Stock [Member] - Restricted Stock [Member]	3 Months Ended
	Mar. 31, 2018$ / sharesshares
2/15/2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Granted | shares	39,950
Grant Date Fair Value Per Share | $ / shares	$ 71.75
Vesting Period	Ratably over 5 years from grant date
2/27/2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Granted | shares	1,150
Grant Date Fair Value Per Share | $ / shares	$ 72.60
Vesting Period	Ratably over 5 years from grant date

Stock Based Compensation Perfor

Stock Based Compensation Performance-based Restricted Stock Textual (Details)	3 Months Ended
	Mar. 31, 2018$ / sharesshares
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0
Employee Stock Plan [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted	16,300
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares	$ 71.75
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage	100.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	16,427

Repurchase Agreements Repurch59

Repurchase Agreements Repurchase Agreements (Details) - Maturity Overnight [Member] - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement	[1]	$ 137,914	$ 162,679
U.S. Government agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement		13,200	16,867
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement		55,946	51,273
Collateralized Mortgage Backed Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Financial Assets Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement		$ 68,768	$ 94,539
[1]	All customer repurchase agreements have an overnight and continuous maturity date.

Derivatives and Hedging Activ60

Derivatives and Hedging Activities (Derivative Positions for Interest Rate Swaps which Qualify as Hedges) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Fair Value	$ 1,974,000		$ 1,616,000
Amortization Of Deferred Hedge Gains Losses	61,000	$ 61,000
Change in Fair Value on Loans Held for Sale	$ (26,000)	$ (147,000)
Positions One [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount			$ 25,000,000
Receive (Variable) Index			3 Month LIBOR
Derivative, Variable Interest Rate			1.54%
Trade Date	Dec. 9, 2008
Derivative, Inception Date	Dec. 10, 2008
Maturity Date	Dec. 10, 2018
Pay Fixed Swap Rate			2.94%
Fair Value			$ (264,000)
Positions Two [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount			$ 25,000,000
Receive (Variable) Index			3 Month LIBOR
Derivative, Variable Interest Rate			1.59%
Trade Date	Apr. 1, 2016
Derivative, Inception Date	Jan. 17, 2017
Maturity Date	Dec. 15, 2021
Pay Fixed Swap Rate			1.36%
Fair Value			$ 772,000
Positions Three [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount			$ 25,000,000
Receive (Variable) Index			3 Month LIBOR
Derivative, Variable Interest Rate			1.59%
Trade Date	Apr. 1, 2016
Derivative, Inception Date	Jan. 17, 2017
Maturity Date	Dec. 15, 2021
Pay Fixed Swap Rate			1.36%
Fair Value			$ 763,000
Positions Four [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount			$ 25,000,000
Receive (Variable) Index			3 Month LIBOR
Derivative, Variable Interest Rate			1.42%
Trade Date	Jul. 18, 2017
Derivative, Inception Date	Aug. 15, 2017
Maturity Date	Aug. 15, 2022
Pay Fixed Swap Rate			1.88%
Fair Value			$ 345,000
Positions Five [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 25,000,000
Receive (Variable) Index	3 Month LIBOR
Derivative, Variable Interest Rate	2.07%
Trade Date	Dec. 9, 2008
Derivative, Inception Date	Dec. 10, 2008
Maturity Date	Dec. 10, 2018
Pay Fixed Swap Rate	2.94%
Fair Value	$ (118,000)
Positions Six [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 25,000,000
Receive (Variable) Index	3 Month LIBOR
Derivative, Variable Interest Rate	2.12%
Trade Date	Apr. 1, 2016
Derivative, Inception Date	Jan. 17, 2017
Maturity Date	Dec. 15, 2021
Pay Fixed Swap Rate	1.36%
Fair Value	$ 1,128,000
Positions Seven [Member] [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 25,000,000
Receive (Variable) Index	3 Month LIBOR
Derivative, Variable Interest Rate	2.12%
Trade Date	Apr. 1, 2016
Derivative, Inception Date	Jan. 17, 2017
Maturity Date	Dec. 15, 2021
Pay Fixed Swap Rate	1.36%
Fair Value	$ 1,116,000
Position Eight [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 25,000,000
Receive (Variable) Index	3 Month LIBOR
Derivative, Variable Interest Rate	1.87%
Trade Date	Jul. 18, 2017
Derivative, Inception Date	Aug. 15, 2017
Maturity Date	Aug. 15, 2022
Pay Fixed Swap Rate	1.88%
Fair Value	$ 796,000
Position Nine [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 50,000,000
Receive (Variable) Index	1 Month LIBOR
Current Rate Paid on Derivative for Interest Rate Swaps which qualify as hedges	1.78%
Trade Date	Jan. 9, 2018
Derivative, Inception Date	Jan. 16, 2018
Maturity Date	Jan. 15, 2023
Pay Fixed Swap Rate	2.24%
Fair Value	$ (678,000)
Position ten [Member]
Details of derivative positions for interest rate swaps which qualify as hedges for accounting purposes
Notional Amount	$ 50,000,000
Receive (Variable) Index	1 Month LIBOR
Current Rate Paid on Derivative for Interest Rate Swaps which qualify as hedges	1.78%
Trade Date	Jan. 9, 2018
Derivative, Inception Date	Jan. 16, 2018
Maturity Date	Jan. 15, 2022
Fair Value	$ (270,000)
Derivative, Cap Price	2.75%
Derivative, Floor Price	1.80%

Derivatives and Hedging Activ61

Derivatives and Hedging Activities (Customer Related Derivative Positions - Not Designated as Hedges) (Details) $ in Thousands		Mar. 31, 2018USD ($)position	Dec. 31, 2017USD ($)position
Summary of customer related derivative positions, not designated as hedging
Fair Value		$ 1,974	$ 1,616
Not Designated as Hedging Instrument | Receive fixed, pay variable | Loan level swaps
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	[1]	248	246
Less than 1 year		$ 34,081	$ 36,023
Less than 2 years		95,894	61,500
Less than 3 years		173,172	152,287
Less than 4 years		59,531	111,147
Thereafter		602,621	591,385
Total		965,299	952,342
Fair Value		$ (11,404)	$ 3,875
Not Designated as Hedging Instrument | Pay fixed, receive variable | Loan level swaps
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	[1]	233	231
Less than 1 year		$ 34,081	$ 36,023
Less than 2 years		95,894	61,500
Less than 3 years		173,172	152,287
Less than 4 years		59,531	111,147
Thereafter		602,621	591,385
Total		965,299	952,342
Fair Value		$ 11,390	$ (3,880)
Not Designated as Hedging Instrument | Buys foreign currency, sells U.S. currency | Foreign exchange contracts
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	[1]	18	15
Less than 1 year		$ 33,089	$ 26,382
Less than 2 years			3,780
Total		33,089	30,162
Fair Value		$ 770	$ 1,202
Not Designated as Hedging Instrument | Buys U.S. currency, sells foreign currency | Foreign exchange contracts
Summary of customer related derivative positions, not designated as hedging
Number of Positions | position	[1]	18	15
Less than 1 year		$ 33,089	$ 26,382
Less than 2 years			3,780
Total		33,089	30,162
Fair Value		$ (751)	$ (1,188)
[1]	The Company may enter into one dealer swap agreement which offsets multiple commercial borrower swap agreements.

Derivatives and Hedging Activ62

Derivatives and Hedging Activities (FV of Derivative Financial Instruments and Classification on Balance Sheet) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 20,870	$ 17,318
Liability Derivatives	18,891	15,693
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Asset, at Fair Value	18,000	15,596
Derivative Asset, Fair Value, Gross Asset	21,040	17,476
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Liability, at Fair Value	17,825	15,429
Liability Derivatives	18,891	15,693
Interest rate swaps [Member] | Derivatives designated as hedges [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Assets, at Fair Value	3,040	1,880
Interest rate swaps [Member] | Derivatives designated as hedges [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Liabilities, at Fair Value	1,066	264
Loan level swaps [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	16,916	14,236
Loan level swaps [Member] | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	16,930	14,241
Foreign exchange contracts | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	914	1,202
Foreign exchange contracts | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	895	1,188
Interest Rate Lock Commitments [Member] | Not Designated as Hedging Instrument | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Instrument Not Designated as a Hedge, Interest Rate Lock Commitments, Asset at Fair Value	151	149
Derivative Instrument Not Designated as a Hedge, Forward Sales Agreements, Asset at Fair Value	19	9
Interest Rate Lock Commitments [Member] | Not Designated as Hedging Instrument | Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Instrument Not Designated as a Hedge, Interest Rate Lock Commitments, Liabilities at Fair Value	0	0
Derivative Instrument Not Designated as a Hedge, Forward Sales Agreements, Liabilities at Fair Value	$ 0	$ 0

Derivatives and Hedging Activ63

Derivatives and Hedging Activities (Derivative Financial Instruments included in OCI and Current Earnings) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent	$ 215	$ 89
Derivatives designated as hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) reclassified from OCI into interest income or interest expense (effective portion)	90	(93)
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	0	0
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Other income	8	37
Interest Expense [Member] | Derivatives designated as hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	0	0
Other expense | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Other income	9	(7)
Changes in fair value of mortgage derivatives | Derivatives designated as hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net	0	0
Changes in fair value of mortgage derivatives | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Other income	(13)	(6)
Total | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Mortgage banking income	12	50
Derivatives designated as hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent	$ 215	$ 89

Derivatives and Hedging Activ64

Derivatives and Hedging Activities (Textual) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Derivative [Line Items]
Derivative, Net Liability Position, Aggregate Fair Value	$ 288,000		$ 4,200,000
Maximum Length of Time Hedged in Interest Rate Cash Flow Hedge	5 years
Gain (Loss) on Sales of Loans, Net	$ 782,000	$ 980,000
Exposure to Institutional Counterparties	17,400,000		7,100,000
Amortization Of Deferred Hedge Gains Losses	61,000	61,000
Customer related positions	3,200,000		$ 9,500,000
Notional amount of fair value hedged derivative	0
Change in Fair Value on Loans Held for Sale	(26,000)	$ (147,000)
Interest Income [Member]
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	53,000
Interest Expense [Member]
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months	$ 656,000

Assets & Liability Derivative P

Assets & Liability Derivative Positions & the Potential Effect of Netting Arrangements - Current Quarter (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		$ 20,870	$ 17,318
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		20,870	17,318
Derivative, Collateral, Obligation to Return Securities	[1]	3,715	5,383
Derivative, Collateral, Obligation to Return Cash		(10,073)	0
Derivative Asset, Fair Value, Amount Offset Against Collateral		7,082	11,935
Derivative Liability, Fair Value, Gross Liability		18,891	15,693
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		18,891	15,693
Derivative, Collateral, Right to Reclaim Securities	[1]	3,715	5,383
Derivative, Collateral, Right to Reclaim Cash		259	3,939
Derivative Liability, Fair Value, Amount Offset Against Collateral		14,917	6,371
Interest rate swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		3,040	1,880
Derivative, Collateral, Obligation to Return Securities	[1]	948	805
Derivative, Collateral, Obligation to Return Cash		(1,128)	0
Derivative Asset, Fair Value, Amount Offset Against Collateral		964	1,075
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		1,066	264
Derivative, Collateral, Right to Reclaim Securities	[1]	948	0
Derivative, Collateral, Right to Reclaim Cash		118	264
Derivative Liability, Fair Value, Amount Offset Against Collateral		0	0
Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		16,916	14,236
Derivative, Collateral, Obligation to Return Securities	[1]	2,767	4,578
Derivative, Collateral, Obligation to Return Cash		(8,945)	0
Derivative Asset, Fair Value, Amount Offset Against Collateral		5,204	9,658
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		16,930	14,241
Derivative, Collateral, Right to Reclaim Securities	[1]	2,767	5,383
Derivative, Collateral, Right to Reclaim Cash		141	3,675
Derivative Liability, Fair Value, Amount Offset Against Collateral		14,022	5,183
Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset		0	0
Derivative Asset		914	1,202
Derivative, Collateral, Obligation to Return Securities	[1]	0	0
Derivative, Collateral, Obligation to Return Cash		0	0
Derivative Asset, Fair Value, Amount Offset Against Collateral		914	1,202
Derivative Liability, Collateral, Right to Reclaim Cash, Offset		0	0
Derivative Liability		895	1,188
Derivative, Collateral, Right to Reclaim Securities	[1]	0	0
Derivative, Collateral, Right to Reclaim Cash		0	0
Derivative Liability, Fair Value, Amount Offset Against Collateral		895	1,188
Other Assets [Member]
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		21,040	17,476
Other Assets [Member] | Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		16,916	14,236
Other Assets [Member] | Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Asset, Fair Value, Gross Asset		914	1,202
Other Liabilities [Member]
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		18,891	15,693
Other Liabilities [Member] | Loan level swaps
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		16,930	14,241
Other Liabilities [Member] | Customer foreign exchange contracts
Offsetting Liabilities [Line Items]
Derivative Liability, Fair Value, Gross Liability		895	1,188
Designated as Hedging Instrument [Member] | Other Assets [Member] | Interest rate swaps
Offsetting Liabilities [Line Items]
Interest Rate Derivative Assets, at Fair Value		3,040	1,880
Designated as Hedging Instrument [Member] | Other Liabilities [Member] | Interest rate swaps
Offsetting Liabilities [Line Items]
Interest Rate Derivative Liabilities, at Fair Value		1,066	264
Customer repurchase agreements and other short-term borrowings(f)
Offsetting Liabilities [Line Items]
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities		0	0
Securities Sold under Agreements to Repurchase, Gross Including Not Subject to Master Netting Arrangement		137,914	162,679
Securities Sold under Agreements to Repurchase, Asset		0	0
Securities Sold under Agreements to Repurchase, Not Subject to Master Netting Arrangement		137,914	162,679
Securities Sold under Agreements to Repurchase, Fair Value of Collateral		137,914	162,679
Securities Sold under Agreements to Repurchase, Amount Offset Against Collateral		$ 0	$ 0
[1]	Reflects offsetting derivative positions with the same counterparty.

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
ASSETS
Trading	$ 1,601	$ 1,324
Trading Securities, Equity	20,075	0
Available for sale	445,750	447,498
Loans held for sale (at fair value)	3,937	4,768
Derivative Asset, Fair Value, Gross Asset	20,870	17,318
Recurring fair value measurements
LIABILITIES
TOTAL RECURRING FAIR VALUE MEASUREMENTS	473,512	455,373
Recurring fair value measurements | Trading Securities [Member]
ASSETS
Trading	1,601	1,324
Recurring fair value measurements | U.S. Government agency securities
ASSETS
Available for sale	34,943	35,430
Recurring fair value measurements | Agency mortgage-backed securities
ASSETS
Available for sale	223,211	215,764
Recurring fair value measurements | Agency collateralized mortgage obligations
ASSETS
Available for sale	135,192	122,012
Recurring fair value measurements | Municipal Bonds [Member]
ASSETS
Available for sale	2,254	2,274
Recurring fair value measurements | Single issuer trust preferred securities issued by banks and insurers
ASSETS
Available for sale	2,005	2,016
Recurring fair value measurements | Pooled trust preferred securities issued by banks and insurers
ASSETS
Available for sale	1,655	1,640
Recurring fair value measurements | Small Business Administration Pooled Securities [Member]
ASSETS
Available for sale	46,490	47,778
Recurring fair value measurements | Equity securities
ASSETS
Trading Securities, Equity	20,075
Available for sale		20,584
Recurring fair value measurements | Loans held for sale
ASSETS
Loans held for sale (at fair value)	3,937	4,768
Recurring fair value measurements | Derivative Financial Instruments, Assets [Member]
ASSETS
Derivative Asset, Fair Value, Gross Asset	21,040	17,476
Recurring fair value measurements | Derivative instruments
LIABILITIES
Liabilities, Fair Value Disclosure, Recurring	18,891	15,693
Nonrecurring fair value measurements
LIABILITIES
TOTAL NONRECURRING FAIR VALUE MEASUREMENTS	32,471	34,179
Nonrecurring fair value measurements | Collateral dependent impaired loans
ASSETS
Assets, Fair Value Disclosure, Nonrecurring	32,113	33,567
Nonrecurring fair value measurements | Other real estate owned and other foreclosed assets
ASSETS
Assets, Fair Value Disclosure, Nonrecurring	358	612
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements
LIABILITIES
TOTAL RECURRING FAIR VALUE MEASUREMENTS	21,676	21,908
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | Trading Securities [Member]
ASSETS
Trading	1,601	1,324
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | Municipal Bonds [Member]
ASSETS
Available for sale		0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | Small Business Administration Pooled Securities [Member]
ASSETS
Available for sale	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring fair value measurements | Equity securities
ASSETS
Trading Securities, Equity	20,075
Available for sale		20,584
Quoted Prices in Active Markets for Identical Assets (Level 1) | Nonrecurring fair value measurements
LIABILITIES
TOTAL NONRECURRING FAIR VALUE MEASUREMENTS	0	0
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements
LIABILITIES
TOTAL RECURRING FAIR VALUE MEASUREMENTS	450,181	431,825
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | U.S. Government agency securities
ASSETS
Available for sale	34,943	35,430
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Agency mortgage-backed securities
ASSETS
Available for sale	223,211	215,764
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Agency collateralized mortgage obligations
ASSETS
Available for sale	135,192	122,012
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Municipal Bonds [Member]
ASSETS
Available for sale	2,254	2,274
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Single issuer trust preferred securities issued by banks and insurers
ASSETS
Available for sale	2,005	2,016
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Small Business Administration Pooled Securities [Member]
ASSETS
Available for sale	46,490	47,778
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Equity securities
ASSETS
Trading Securities, Equity	0
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Loans held for sale
ASSETS
Available for sale	3,937	4,768
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Derivative Financial Instruments, Assets [Member]
ASSETS
Derivative Asset, Fair Value, Gross Asset	21,040	17,476
Significant Other Observable Inputs (Level 2) | Recurring fair value measurements | Derivative instruments
LIABILITIES
Liabilities, Fair Value Disclosure, Recurring	18,891	15,693
Significant Other Observable Inputs (Level 2) | Nonrecurring fair value measurements
LIABILITIES
TOTAL NONRECURRING FAIR VALUE MEASUREMENTS	0	0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements
LIABILITIES
TOTAL RECURRING FAIR VALUE MEASUREMENTS	1,655	1,640
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | Municipal Bonds [Member]
ASSETS
Available for sale		0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | Pooled trust preferred securities issued by banks and insurers
ASSETS
Available for sale	1,655	1,640
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | Small Business Administration Pooled Securities [Member]
ASSETS
Available for sale	0	0
Significant Unobservable Inputs (Level 3) | Recurring fair value measurements | Equity securities
ASSETS
Trading Securities, Equity	0
Significant Unobservable Inputs (Level 3) | Nonrecurring fair value measurements
LIABILITIES
TOTAL NONRECURRING FAIR VALUE MEASUREMENTS	32,471	34,179
Significant Unobservable Inputs (Level 3) | Nonrecurring fair value measurements | Collateral dependent impaired loans
ASSETS
Assets, Fair Value Disclosure, Nonrecurring	32,113	33,567
Significant Unobservable Inputs (Level 3) | Nonrecurring fair value measurements | Other real estate owned and other foreclosed assets
ASSETS
Assets, Fair Value Disclosure, Nonrecurring	$ 358	$ 612

Fair Value Measurements (Deta67

Fair Value Measurements (Details 1) - Pooled trust preferred securities - Significant Unobservable Inputs (Level 3) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reconciliation for all assets and liabilities measured at fair value on a recurring basis
Beginning Balance	$ 1,640	$ 1,584
Included in Other Comprehensive Income	21	11
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, (Sales), Issuances, (Settlements)	(6)	1
Ending Balance	$ 1,655	$ 1,596

Fair Value Measurements (Deta68

Fair Value Measurements (Details 2) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Mar. 31, 2018	Dec. 31, 2017
Investments in securities that are classified as level 3
Available-for-sale Securities		$ 445,750	$ 447,498
Discounted cash flow methodology [Member] | Significant Unobservable Inputs (Level 3) | Weighted Average [Member]
Investments in securities that are classified as level 3
Cumulative Prepayment		2.40%	2.50%
Cumulative Default		12.30%	12.40%
Loss Given Default		94.40%	94.30%
Cure Given Default		60.90%	60.90%
Pooled trust preferred securities | Significant Unobservable Inputs (Level 3)
Investments in securities that are classified as level 3
Available-for-sale Securities		$ 1,655	$ 1,640
Pooled trust preferred securities | Discounted cash flow methodology [Member] | Significant Unobservable Inputs (Level 3) | Minimum [Member]
Investments in securities that are classified as level 3
Cumulative Prepayment		0.00%	0.00%
Cumulative Default		5.00%	5.00%
Loss Given Default		85.00%	85.00%
Cure Given Default		0.00%	0.00%
Pooled trust preferred securities | Discounted cash flow methodology [Member] | Significant Unobservable Inputs (Level 3) | Maximum [Member]
Investments in securities that are classified as level 3
Cumulative Prepayment		60.00%	61.00%
Cumulative Default		100.00%	100.00%
Loss Given Default		100.00%	100.00%
Cure Given Default		75.00%	75.00%
Collateral dependent impaired loans | Significant Unobservable Inputs (Level 3)
Investments in securities that are classified as level 3
Fair Value	[1]	$ 32,113	$ 33,567
Other real estate owned and other foreclosed assets | Significant Unobservable Inputs (Level 3)
Investments in securities that are classified as level 3
Fair Value	[1]	$ 358	$ 612
[1]	Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various Level 3 inputs which are not identifiable. Appraisals may be adjusted by management for qualitative factors such as economic factors and estimated liquidation expenses. The range of these possible adjustments may vary.

Fair Value Measurements (Deta69

Fair Value Measurements (Details 3) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		$ 20,075	$ 0
ASSETS
Held-to-maturity Securities		528,861	497,688
Held to Maturity, Fair Value, Total		517,555	494,194
Loans, net of allowance for loan losses(b)		6,301,194	6,294,910
Federal Home Loan Bank Stock		13,027	11,597
Bank Owned Life Insurance		152,568	151,528
LIABILITIES
Federal Home Loan Bank borrowings(f)		53,257	53,264
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust		73,075	73,073
Subordinated Debt		34,693	34,682
Deposits [Member]
LIABILITIES
Time certificates of deposits(f)	[1]	6,096,756	6,084,952
Accrued Liabilities, Fair Value Disclosure	[1]	6,096,756	6,084,952
Time certificates of deposits(f)
LIABILITIES
Time certificates of deposits(f)	[2]	654,755	644,301
Accrued Liabilities, Fair Value Disclosure	[2]	646,819	639,060
Federal Home Loan Bank borrowings(f)
LIABILITIES
Federal Home Loan Bank borrowings(f)	[2]	53,257	53,264
Federal Home Loan Bank Borrowings, Fair Value Disclosure	[2]	52,176	52,111
Customer repurchase agreements and other short-term borrowings(f)
LIABILITIES
Customer repurchase agreements	[2]	137,914	162,679
Accrued Liabilities, Fair Value Disclosure	[2]	137,914	162,679
Junior subordinated debentures(g)
LIABILITIES
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	[3]	73,075	73,073
Accrued Liabilities, Fair Value Disclosure	[3]	72,283	74,680
Subordinated debentures(f)
LIABILITIES
Subordinated Debt	[2]	34,693	34,682
Accrued Liabilities, Fair Value Disclosure	[2]	32,429	32,707
Significant Other Observable Inputs (Level 2) | Deposits [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[1]	6,096,756	6,084,952
Significant Other Observable Inputs (Level 2) | Time certificates of deposits(f)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[2]	646,819	639,060
Significant Other Observable Inputs (Level 2) | Federal Home Loan Bank borrowings(f)
LIABILITIES
Federal Home Loan Bank Borrowings, Fair Value Disclosure	[2]	52,176
Accrued Liabilities, Fair Value Disclosure	[2]		52,111
Significant Other Observable Inputs (Level 2) | Junior subordinated debentures(g)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[3]	72,283	74,680
Significant Unobservable Inputs (Level 3) | Customer repurchase agreements and other short-term borrowings(f)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[2]	137,914	162,679
Significant Unobservable Inputs (Level 3) | Subordinated debentures(f)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	[2]	32,429	32,707
Fair Value, Measurements, Recurring [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		20,075
Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		20,075
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		0
Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3) | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities, Equity		0
U.S. Treasury securities
ASSETS
Held-to-maturity Securities	[4]	1,005	1,006
Held to Maturity, Fair Value, Total	[4]	1,021	1,035
U.S. Treasury securities | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	1,021	1,035
Agency mortgage-backed securities
ASSETS
Held-to-maturity Securities	[4]	192,961	204,768
Held to Maturity, Fair Value, Total	[4]	190,409	205,823
Agency mortgage-backed securities | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	190,409	205,823
Agency collateralized mortgage obligations
ASSETS
Held-to-maturity Securities	[4]	306,395	262,998
Held to Maturity, Fair Value, Total	[4]	297,818	258,408
Agency collateralized mortgage obligations | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	297,818	258,408
Single issuer trust preferred securities issued by banks
ASSETS
Held-to-maturity Securities	[4]	1,500	1,500
Held to Maturity, Fair Value, Total	[4]	1,521	1,529
Single issuer trust preferred securities issued by banks | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	1,521	1,529
Small Business Administration Pooled Securities [Member]
ASSETS
Held-to-maturity Securities	[4]	27,000	27,416
Held to Maturity, Fair Value, Total	[4]	26,786	27,399
Small Business Administration Pooled Securities [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
ASSETS
Held to Maturity, Fair Value, Total	[4]	0	0
Small Business Administration Pooled Securities [Member] | Significant Other Observable Inputs (Level 2)
ASSETS
Held to Maturity, Fair Value, Total	[4]	26,786	27,399
Small Business Administration Pooled Securities [Member] | Significant Unobservable Inputs (Level 3)
ASSETS
Held to Maturity, Fair Value, Total	[4]	0	0
Loans, net of allowance for loan losses(b)
ASSETS
Loans, net of allowance for loan losses(b)	[5]	6,269,081	6,261,343
Loans Receivable, Fair Value Disclosure	[5]	6,103,312	6,116,051
Loans, net of allowance for loan losses(b) | Significant Unobservable Inputs (Level 3)
ASSETS
Loans Receivable, Fair Value Disclosure	[5]	6,103,312	6,116,051
Investment in Federal Home Loan Bank Stock [Member]
ASSETS
Federal Home Loan Bank Stock	[6]	13,027	11,597
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[6]	13,027	11,597
Investment in Federal Home Loan Bank Stock [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
ASSETS
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[6]	0	0
Investment in Federal Home Loan Bank Stock [Member] | Significant Other Observable Inputs (Level 2)
ASSETS
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[6]	13,027	11,597
Investment in Federal Home Loan Bank Stock [Member] | Significant Unobservable Inputs (Level 3)
ASSETS
Investment in Federal Home Loan Bank Stock, Fair Value Disclosure	[6]	0	0
Cash Surrender Value [Member]
ASSETS
Cash Surrender Value, Fair Value Disclosure	[7]	152,568	151,528
Bank Owned Life Insurance	[7]	152,568	151,528
Cash Surrender Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
ASSETS
Cash Surrender Value, Fair Value Disclosure	[7]	0	0
Cash Surrender Value [Member] | Significant Other Observable Inputs (Level 2)
ASSETS
Cash Surrender Value, Fair Value Disclosure	[7]	152,568	151,528
Cash Surrender Value [Member] | Significant Unobservable Inputs (Level 3)
ASSETS
Cash Surrender Value, Fair Value Disclosure	[7]	$ 0	$ 0
[1]	Fair value of demand deposits, savings and interest checking accounts and money market deposits is the amount payable on demand at the reporting date.
[2]	Fair value was determined by discounting anticipated future cash payments using rates currently available for instruments with similar remaining maturities.
[3]	Fair value was determined based upon market prices of securities with similar terms and maturities.
[4]	The fair values presented are based on quoted market prices, where available. If quoted market prices are not available, fair values are based on quoted market prices of comparable instruments and/or discounted cash flow analysis.
[5]	estimated solely by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities or cash flows. Additionally, this amount excludes collateral dependent impaired loans, which are deemed to be marked to fair value on a nonrecurring basis.
[6]	FHLB stock has no quoted market value and is carried at cost, therefore the carrying amount approximates fair value.
[7]	Cash surrender value of life insurance is recorded at its cash surrender value (or the amount that can be realized upon surrender of the policy), therefore carrying amount approximates fair value.

Revenue Recognition Disaggregat

Revenue Recognition Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue from Contract with Customer [Abstract]
Service Charges on Deposit Accounts	$ 4,431	$ 4,544
Merchant Discount Fees	3,405	3,121
ATM Fees	654	687
Wealth management and advisory services	5,582	5,137
Fees and Commissions Investment Management	560	477
Merchant Processing Income	431	293
Other noninterest income - ASC 606	$ 974	$ 822

Revenue Recognition Contract wi

Revenue Recognition Contract with Customer, Asset (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Investment Management Income Receivable	$ 1,839	$ 1,934

Comprehensive Income_Loss (Comp

Comprehensive Income/Loss (Comprehensive Income/(Loss) Presented Net of Taxes) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2009
Equity [Abstract]
Deferred Gain Loss On Cash Flow Hedge		$ 122		$ 137	$ 1,400
COMPREHENSIVE INCOME
Change in fair value of securities available for sale, pre tax amount		(7,240)	$ 896
Change in fair value of securities available for sale, tax (expense) benefit		1,772	(364)
Change in fair value of securities available for sale, after tax amount		(5,468)	532
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax		0	1
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax		0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax		0	1
Change in fair value of securities available for sale, pre tax amount		(7,240)	895
Change in fair value of securities available for sale, tax (expense) benefit		1,772	(364)
Change in fair value of securities available for sale, after tax amount		(5,468)	531
Change in fair value of cash flow hedges, pre tax amount		386	58
Change in fair value of cash flow hedges, tax (expense) benefit		(106)	(24)
Change in fair value of cash flow hedges, after tax amount		280	34
Less: net cash flow hedge losses reclassified into interest on borrowings expense, pre tax amount	[1]	90	(93)
Less: net cash flow hedge losses reclassified into earnings, tax (expense) benefit	[1]	(25)	38
Less: net cash flow hedge losses reclassified into interest on borrowings expense, after tax	[1]	65	(55)
Net change in fair value of cash flow hedges, pre tax amount		296	151
Net change in fair value of cash flow hedges, tax (expense) benefit		(81)	(62)
Net change in fair value of cash flow hedges		215	89
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax		0	(7)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax		0	3
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax		0	(4)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax		94	70
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax		(26)	(29)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax		68	41
Amortization of certain costs included in net periodic retirement costs, pre tax amount		69	69
Amortization of certain costs included in net periodic retirement costs, tax (expense) benefit		(20)	(28)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax		49	41
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	[2]	163	132
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	[2]	(46)	(54)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	[2]	117	78
Total other comprehensive income, pre tax amount		(6,781)	1,178
Total other comprehensive income, tax (expense) benefit		1,645	(480)
Total other comprehensive income, after tax amount		$ (5,136)	$ 698
[1]	Includes the amortization of the remaining balance of a realized but unrecognized gain, net of tax, from the termination of interest rate swaps in 2009. The original gain of $1.4 million, net of tax, is being recognized in earnings through December 2018, the original maturity date of the swap. The balance of this gain has amortized to $122,000 and $137,000 at March 31, 2018 and December 31, 2017, respectively.
[2]	The amortization of prior service costs is included in the computation of net periodic pension cost as disclosed in the Employee Benefit Plans footnote in the Company's Annual Report on Form 10-K for the year ended December 31, 2017, filed with the Securities and Exchange Commission.

Comprehensive Income_Loss (Co73

Comprehensive Income/Loss (Comprised of the following Components) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment		$ 0
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		0	$ 177	[1]
Beginning Balance		(1,831)	(1,337)
Net change in other comprehensive income (loss)		(5,136)	698
Ending Balance		(8,195)	(639)
Unrealized Gain on Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment		(111)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		(831)
Beginning Balance		(504)	173
Net change in other comprehensive income (loss)		(5,468)	531
Ending Balance		(6,914)	704
Unrealized Gain (Loss) on Cash Flow Hedge
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment		205
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		0
Beginning Balance		948	361
Net change in other comprehensive income (loss)		259	125
Ending Balance		1,412	486
Deferred Gain on Hedge Transactions
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment		29
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		0
Beginning Balance		137	281
Net change in other comprehensive income (loss)		(44)	(36)
Ending Balance		122	245
Defined Benefit Postretirement Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment		(520)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		0
Beginning Balance		(2,412)	(2,152)
Net change in other comprehensive income (loss)		117	78
Ending Balance		(2,815)	(2,074)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment	[2]	(397)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	[3]	(831)
Net change in other comprehensive income (loss)		$ (5,136)	$ 698
[1]	Represents adjustment needed to reflect the cumulative impact on retained earnings for previously recognized stock based compensation, which included an adjustment for estimated forfeitures. Pursuant to the Company's adoption of Accounting Standards Update 2016-09, the Company has elected to recognize stock based compensation without inclusion of a forfeiture estimate, and as such has recognized this adjustment to present retained earnings consistent with this election.
[2]	Represents adjustment needed to reflect the cumulative impact on retained earnings for reclassification of the income tax effects attributable to accumulated other comprehensive income, as a result of the Tax Cuts and Jobs Act (the "Tax Act"). Pursuant to the Company's adoption of Accounting Standards Update 2018-02, the Company has elected to reclassify amounts stranded in other comprehensive income to retained earnings.
[3]	Represents adjustment needed to reflect the cumulative impact on retained earnings for the classification and measurement of investments in equity securities. Pursuant to the Company's adoption of Accounting Standards Update 2016-01, the Company's investments in equity securities will no longer be classified as available for sale, therefore the Company was required to reclassify the net unrealized gain recognized on the change in fair value of these equity securities from other comprehensive income to retained earnings.

Comprehensive Income_Loss (Deta

Comprehensive Income/Loss (Details Textual) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2009
Equity [Abstract]
Gain on interest rate swaps	$ 122	$ 137	$ 1,400

Commitments and contingencies F

Commitments and contingencies Financial Instruments with Off-Balance Sheet Risk (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Commitments to Extend Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	$ 2,502,731	$ 2,443,478
Standby Letters of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	15,994	15,534
Deferred standby letter of credit fees [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability	$ 114	$ 102

Commitments and contingencies T

Commitments and contingencies Textual (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Other Commitments [Line Items]
Operating Leases, Rent Expense	$ 2.5	$ 2
Cash Reserve Deposit Required and Made	$ 0		$ 35.8
Minimum [Member]
Other Commitments [Line Items]
Operating Leases, Lease Renewal Period Option	5 years
Maximum [Member]
Other Commitments [Line Items]
Operating Leases, Lease Renewal Period Option	10 years

Investments is Low Income Hou77

Investments is Low Income Housing Tax Credits Investments in Qualified Affordable Housing Projects (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018		Dec. 31, 2017
Investments in Affordable Housing Projects [Abstract]
Original investment value	$ 47,408		$ 47,399
Amortization Method Qualified Affordable Housing Project Investments	34,153		35,225
Capital commitment relating to low income housing project investments	3,332		4,536
Tax credits and benefits	5,494	[1]	5,654
Amortization of investments	4,330	[2]	4,402	[3]
Net income tax benefit	$ 1,165	[4]	$ 1,253
[1]	(1) This amount reflects anticipated tax credits and tax benefits for the full year ended December 31, 2018.
[2]	(2) The amortization amount reduces the tax credits and benefits anticipated for the full year ended December 31, 2018.
[3]	(4) The 2017 amount is inclusive of $466,000 related to the revaluation of Low Income Housing tax credit investments as a result of the Tax Act.
[4]	(3) This amount represents the net tax benefit expected to be realized for the full year ended December 31, 2018 in determining the Company's effective tax rate.