Century Bancorp (CNBKA) 10-Q 6 Aug 15 2015 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 31, 2015
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q2
Trading Symbol	CNBKA
Entity Registrant Name	CENTURY BANCORP INC
Entity Central Index Key	812,348
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		3,600,729
Class B Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		1,967,180

Consolidated Balance Sheets (un

Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Assets
Cash and due from banks	$ 60,547	$ 43,367
Federal funds sold and interest-bearing deposits in other banks	24,522	261,990
Total cash and cash equivalents	85,069	305,357
Short-term investments	2,139	2,131
Securities available-for-sale, amortized cost $440,044 and $448,210, respectively	440,059	448,390
Securities held-to-maturity, fair value $1,689,572 and $1,413,603, respectively	1,683,568	1,406,792
Federal Home Loan Bank of Boston stock, at cost	27,748	24,916
Loans, net
Commercial and industrial	291,142	149,732
Municipal	87,241	41,850
Construction and land development	26,521	22,744
Commercial real estate	713,770	696,272
Residential real estate	248,103	257,305
Home equity	167,271	151,275
Consumer and other	10,646	12,188
Total loans, net	1,544,694	1,331,366
Less: allowance for loan losses	22,245	22,318
Net loans	1,522,449	1,309,048
Bank premises and equipment	24,416	24,182
Accrued interest receivable	7,281	6,241
Goodwill	2,714	2,714
Other assets	118,375	94,265
Total assets	3,913,818	3,624,036
Deposits:
Demand deposits	512,167	484,928
Savings and NOW deposits	1,054,132	978,619
Money Market Accounts	902,106	890,899
Time deposits	383,284	383,145
Total deposits	2,851,689	2,737,591
Securities sold under agreements to repurchase	283,830	212,360
Other borrowed funds	485,500	395,500
Subordinated debentures	36,083	36,083
Due to broker	2,418
Other liabilities	49,925	50,002
Total liabilities	$ 3,709,445	$ 3,431,536
Stockholders' Equity
Preferred stock-$1.00 par value; 100,000 shares authorized; no shares issued and outstanding
Additional paid-in capital	$ 12,292	$ 12,292
Retained earnings	210,196	200,411
Stockholders' equity before adjustment of accumulated other comprehensive income (loss)	228,056	218,271
Unrealized (losses) gains on securities available-for-sale, net of taxes	(23)	77
Unrealized losses on securities transferred to held-to-maturity, net of taxes	(8,717)	(10,479)
Pension liability, net of taxes	(14,943)	(15,369)
Total accumulated other comprehensive loss, net of taxes	(23,683)	(25,771)
Total stockholders' equity	204,373	192,500
Total liabilities and stockholders' equity	3,913,818	3,624,036
Class A Common Stock [Member]
Stockholders' Equity
Common stock value	3,601	3,601
Total stockholders' equity	3,601	3,601
Class B Common Stock [Member]
Stockholders' Equity
Common stock value	1,967	1,967
Total stockholders' equity	$ 1,967	$ 1,967

Consolidated Balance Sheets (u3

Consolidated Balance Sheets (unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Amortized cost	$ 440,044	$ 448,210
Held-to-maturity securities, fair value	$ 1,689,572	$ 1,413,603
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	100,000	100,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A Common Stock [Member]
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	10,000,000	10,000,000
Common stock, shares issued	3,600,729	3,600,729
Class B Common Stock [Member]
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	5,000,000	5,000,000
Common stock, shares issued	1,967,180	1,976,180

Consolidated Statements of Inco

Consolidated Statements of Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Interest income
Loans	$ 12,470	$ 12,611	$ 24,546	$ 25,060
Securities held-to-maturity	9,371	8,020	17,539	15,800
Securities available-for-sale	737	794	1,469	1,614
Federal funds sold and interest-bearing deposits in other banks	97	129	293	211
Total interest income	22,675	21,554	43,847	42,685
Interest expense
Savings and NOW deposits	692	660	1,320	1,269
Money market accounts	734	669	1,516	1,308
Time deposits	1,207	1,141	2,363	2,226
Securities sold under agreements to repurchase	128	93	242	194
Other borrowed funds and subordinated debentures	2,200	2,237	4,285	4,420
Total interest expense	4,961	4,800	9,726	9,417
Net interest income	17,714	16,754	34,121	33,268
Provision for loan losses		450	200	1,050
Net interest income after provision for loan losses	17,714	16,304	33,921	32,218
Other operating income
Service charges on deposit accounts	1,934	2,012	3,847	4,046
Lockbox fees	888	845	1,676	1,622
Net gains on sales of securities	118		118
Gains on sales of mortgage loans	418	81	517	88
Other income	852	677	1,557	1,329
Total other operating income	4,210	3,615	7,715	7,085
Operating expenses
Salaries and employee benefits	9,480	8,776	18,614	17,651
Occupancy	1,517	1,322	3,122	2,764
Equipment	659	585	1,252	1,157
FDIC assessments	545	494	1,048	974
Other	3,565	2,912	6,268	5,702
Total operating expenses	15,766	14,089	30,304	28,248
Income before income taxes	6,158	5,830	11,332	11,055
Provision for income taxes	233	231	448	524
Net income	5,925	5,599	10,884	10,531
Class A Common Stock [Member]
Operating expenses
Net income	$ 4,654	$ 4,394	$ 8,549	$ 8,259
Share data:
Weighted average number of shares outstanding, basic	3,600,729	3,589,125	3,600,729	3,585,773
Weighted average number of shares outstanding, diluted	5,567,909	5,558,032	5,567,909	5,558,105
Basic earnings per share	$ 1.29	$ 1.22	$ 2.37	$ 2.30
Diluted earnings per share	$ 1.06	$ 1.01	$ 1.95	$ 1.89
Class B Common Stock [Member]
Operating expenses
Net income	$ 1,271	$ 1,205	$ 2,335	$ 2,272
Share data:
Weighted average number of shares outstanding, basic	1,967,180	1,967,580	1,967,180	1,970,880
Weighted average number of shares outstanding, diluted	1,967,180	1,967,580	1,967,180	1,970,880
Basic earnings per share	$ 0.65	$ 0.61	$ 1.19	$ 1.15
Diluted earnings per share	$ 0.65	$ 0.61	$ 1.19	$ 1.15

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 5,925	$ 5,599	$ 10,884	$ 10,531
Unrealized gains (losses) on securities:
Unrealized (losses) gains arising during period	1	262	(29)	505
Less: reclassification adjustment for gains included in net income	(71)		(71)
Total unrealized (losses) gains on securities	(70)	262	(100)	505
Accretion of net unrealized losses transferred	1,027	808	1,762	1,732
Defined benefit pension plans:
Amortization of prior service cost and loss included in net periodic benefit cost	213	56	426	113
Other comprehensive income (loss)	1,170	1,126	2,088	2,350
Comprehensive income (loss)	$ 7,095	$ 6,725	$ 12,972	$ 12,881

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity (unaudited) - USD ($) $ in Thousands	Total	Class A Common Stock [Member]	Class B Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member]Class A Common Stock [Member]	Retained Earnings [Member]Class B Common Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 31, 2013	$ 176,472	$ 3,580	$ 1,976	$ 11,932	$ 180,747			$ (21,763)
Net income	10,531	8,259	2,272		10,531
Other comprehensive income, net of tax:
Unrealized holding (losses) gains arising during period, net of taxes	505							505
Unrealized holding (losses) gains arising during period, net of taxes	505
Accretion of unrealized losses on securities transferred to held-to-maturity net of taxes	1,732							1,732
Amortization of prior service cost and loss included in net periodic benefit cost	113							113
Conversion of class B common stock to class A common stock		8
Conversion of class B common stock to class A common stock			(8)
Stock options exercised	4	1		3
Cash dividends		(859)	(237)			$ (859)	$ (237)
Ending balance at Jun. 30, 2014	188,261	3,589	1,968	11,935	190,182			(19,413)
Beginning balance at Dec. 31, 2014	192,500	3,601	1,967	12,292	200,411			(25,771)
Net income	10,884	8,549	2,335		10,884
Other comprehensive income, net of tax:
Unrealized holding (losses) gains arising during period, net of taxes	(29)
Unrealized holding (losses) gains arising during period, net of taxes	(100)							(100)
Accretion of unrealized losses on securities transferred to held-to-maturity net of taxes	1,762							1,762
Amortization of prior service cost and loss included in net periodic benefit cost	426							426
Cash dividends		(865)	(234)			$ (865)	$ (234)
Ending balance at Jun. 30, 2015	$ 204,373	$ 3,601	$ 1,967	$ 12,292	$ 210,196			$ (23,683)

Consolidated Statements of Cha7

Consolidated Statements of Changes in Shareholders' Equity (unaudited) (Parenthetical) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Unrealized holding (losses) gains arising during period, taxes	$ 64	$ 339
Realized net gains	71
Accretion of net unrealized losses transferred during the period, taxes	943	1,061
Pension liability adjustment, taxes	$ 284	$ 75
Stock options exercised, shares		125
Class A Common Stock [Member]
Conversion of class B common stock to class A common stock, shares		8,600
Cash dividends, per share	$ 0.24	$ 0.24
Class B Common Stock [Member]
Conversion of class B common stock to class A common stock, shares		8,600
Cash dividends, per share	$ 0.12	$ 0.12

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 10,884	$ 10,531
Adjustments to reconcile net income to net cash (used in) provided by operating activities:
Gain on sales of mortgage loans	(517)	(88)
Net gains on sales of securities	(118)
Provision for loan losses	200	1,050
Deferred income taxes	(819)	(1,547)
Net depreciation and amortization	1,639	1,630
Increase in accrued interest receivable	(1,040)	(175)
Increase in other assets	(13,357)	(2,192)
Increase in other liabilities	632	454
Net cash (used in) provided by operating activities	(2,496)	9,663
CASH FLOWS FROM INVESTING ACTIVITIES:
Proceeds from maturities of short-term investments		3,561
Purchase of short-term investments	(8)	(1,069)
Proceeds from calls/maturities of securities available-for-sale	91,052	71,155
Proceeds from sales of securities available-for-sale	21,215
Purchase of securities available-for-sale	(115,690)	(100,084)
Proceeds from calls/maturities of securities held-to-maturity	169,457	106,312
Purchase of securities held-to-maturity	(443,705)	(152,901)
Net increase in loans	(249,003)	(55,701)
Proceeds from sales of portfolio loans	35,941	6,082
Capital expenditures	(1,520)	(1,252)
Net cash used in investing activities	(492,261)	(123,897)
CASH FLOWS FROM FINANCING ACTIVITIES:
Net increase in time deposits	139	5,965
Net increase in demand, savings, money market and NOW deposits	113,959	128,534
Net proceeds from exercise of stock options		4
Cash dividends	(1,099)	(1,096)
Net increase (decrease) in securities sold under agreements to repurchase	71,470	(34,430)
Net increase in other borrowed funds	90,000	12,356
Net cash provided by financing activities	274,469	111,333
Net decrease in cash and cash equivalents	(220,288)	(2,901)
Cash and cash equivalents at beginning of period	305,357	94,678
Cash and cash equivalents at end of period	85,069	91,777
Cash paid during the period for:
Interest	9,646	9,421
Income taxes	2,730	1,991
Change in unrealized gains (losses) on securities available-for-sale, net of taxes	(100)	505
Change in unrealized losses on securities transferred to held-to-maturity, net of taxes	1,762	1,732
Pension liability adjustment, net of taxes	426	113
Due (from) to broker	(8,764)	$ 2,000
Loans transferred to other real estate owned	$ 1,916

Basis of Financial Statement Pr

Basis of Financial Statement Presentation	6 Months Ended
	Jun. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Financial Statement Presentation	Note 1. Basis of Financial Statement Presentation The consolidated financial statements include the accounts of Century Bancorp, Inc. (the “Company”) and its wholly owned subsidiary, Century Bank and Trust Company (the “Bank”). The consolidated financial statements also include the accounts of the Bank’s wholly owned subsidiaries, Century Subsidiary Investments, Inc. (“CSII”), Century Subsidiary Investments, Inc. II (“CSII II”), Century Subsidiary Investments, Inc. III (“CSII III”) and Century Financial Services Inc. (“CFSI”). CSII, CSII II, and CSII III are engaged in buying, selling and holding investment securities. CFSI has the power to engage in financial agency, securities brokerage, and investment and financial advisory services and related securities credit. The Company also owns 100% of Century Bancorp Capital Trust II (“CBCT II”). The entity is an unconsolidated subsidiary of the Company. All significant intercompany accounts and transactions have been eliminated in consolidation. The Company provides a full range of banking services to individual, business and municipal customers in Massachusetts. As a bank holding company, the Company is subject to the regulation and supervision of the Federal Reserve Board. The Bank, a state chartered financial institution, is subject to supervision and regulation by applicable state and federal banking agencies, including the Federal Reserve Board, the Federal Deposit Insurance Corporation (the “FDIC”) and the Commonwealth of Massachusetts Commissioner of Banks. The Bank is also subject to various requirements and restrictions under federal and state law, including requirements to maintain reserves against deposits, restrictions on the types and amounts of loans that may be granted and the interest that may be charged thereon, and limitations on the types of investments that may be made and the types of services that may be offered. Various consumer laws and regulations also affect the operations of the Bank. In addition to the impact of regulation, commercial banks are affected significantly by the actions of the Federal Reserve Board as it attempts to control the money supply and credit availability in order to influence the economy. All aspects of the Company’s business are highly competitive. The Company faces aggressive competition from other lending institutions and from numerous other providers of financial services. The Company has one reportable operating segment. The financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America and general practices within the banking industry. In preparing the financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the date of the balance sheet and revenues and expenses for the period. Actual results could differ from those estimates. The Company’s quarterly report on Form 10-Q should be read in conjunction with the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2014, as filed with the Securities and Exchange Commission. Material estimates that are susceptible to change in the near term relate to the allowance for loan losses. Management believes that the allowance for loan losses is adequate based on independent appraisals and review of other factors, including historical charge-off rates with additional allocations based on risk factors for each category and general economic factors. While management uses available information to recognize loan losses, future additions to the allowance for loan losses may be necessary based on changes in economic conditions. In addition, regulatory agencies periodically review the Company’s allowance for loan losses. Such agencies may require the Company to recognize additions to the allowance for loan losses based on their judgments about information available to them at the time of their examination. Certain reclassifications are made to prior-year amounts whenever necessary to conform with the current-year presentation.

Securities Available-for-Sale

Securities Available-for-Sale	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Securities Available-for-Sale	Note 2. Securities Available-for-Sale June 30, 2015 December 31, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) U.S. Treasury $ 1,999 $ — $ 2 $ 1,997 $ 1,999 $ 1 $ — $ 2,000 Small Business Administration 6,446 48 — 6,494 6,684 33 — 6,717 U.S. Government Agency and Sponsored Enterprises Mortgage Backed Securities 272,775 1,114 326 273,563 336,158 1,387 452 337,093 Privately Issued Residential Mortgage Backed Securities 1,654 4 17 1,641 1,894 5 25 1,874 Obligations Issued by States and Political Subdivisions 153,417 — 876 152,541 97,657 — 873 96,784 Other Debt Securities 3,600 14 115 3,499 3,600 24 100 3,524 Equity Securities 153 171 — 324 218 180 — 398 Total $ 440,044 $ 1,351 $ 1,336 $ 440,059 $ 448,210 $ 1,630 $ 1,450 $ 448,390 During the third quarter of 2013, securities available-for-sale with an amortized cost of $1,012,370,000 were transferred to securities held-to-maturity at their fair value of $987,037,000 in response to rising interest rates. Rising interest rates have the potential to increase unrealized losses on the available-for-sale portfolio. The transfer was implemented to lessen the effects of rising interest rates. Included in U.S. Government Sponsored Enterprise Securities and U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities are securities at fair value pledged to secure public deposits and repurchase agreements amounting to $256,228,000 and $301,038,000 at June 30, 2015 and December 31, 2014, respectively. Also included in securities available-for-sale are securities pledged for borrowing at the Federal Home Loan Bank of Boston amounting to $22,268,000 and $24,810,000 at June 30, 2015 and December 31, 2014, respectively. The Company realized gross gains of $118,000 from the proceeds of $21,215,000 from the sales of available-for-sale securities for the six months ended June 30, 2015. Debt securities of Government Sponsored Enterprises primarily refer to debt securities of Fannie Mae and Freddie Mac. The following table shows the maturity distribution of the Company’s securities available-for-sale at June 30, 2015. Amortized Cost Fair Value (in thousands) Within one year $ 147,326 $ 147,327 After one but within five years 161,584 162,236 After five but within ten years 121,460 121,600 More than 10 years 8,021 7,187 Non-maturing 1,653 1,709 Total $ 440,044 $ 440,059 The weighted average remaining life of investment securities available-for-sale at June 30, 2015 was 3.7 years. The contractual maturities, which were used in the table above, of mortgage-backed securities, will differ from the actual maturities, due to the ability of the issuers to prepay underlying obligations. As of June 30, 2015 and December 31, 2014, management concluded that the unrealized losses of its investment securities are temporary in nature since they are not related to the underlying credit quality of the issuers, and the Company does not intend to sell these debt securities and it is not more likely than not that it will be required to sell these debt securities before the anticipated recovery of its remaining amortized cost. In making its other-than-temporary impairment evaluation, the Company considered that the principal and interest on these securities are from issuers that are investment grade. The change in the unrealized losses on the state and municipal securities and the nonagency mortgage-backed securities was primarily caused by changes in credit spreads and liquidity issues in the marketplace. The unrealized loss on U.S. Government Sponsored Enterprises and U.S. Government Sponsored Enterprises Mortgage Backed Securities related primarily to interest rates and not credit quality and because the Company has the ability and intent to hold these investments until recovery of fair value, which may be maturity. The Company does not consider these investments to be other-than-temporarily impaired. In evaluating the underlying credit quality of a security, management considers several factors such as the credit rating of the obligor and the issuer, if applicable. Internal reviews of issuer financial statements are performed as deemed necessary. In the case of privately issued mortgage-backed securities, the performance of the underlying loans is analyzed as deemed necessary to determine the estimated future cash flows of the securities. Factors considered include the level of subordination, current and estimated future default rates, current and estimated prepayment rates, estimated loss severity rates, geographic concentrations and origination dates of underlying loans. In the case of marketable equity securities, the severity of the unrealized loss, the length of time the unrealized loss has existed, and the issuer’s financial performance are considered. The following table shows the temporarily impaired securities of the Company’s available-for-sale portfolio at June 30, 2015. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for 12 months or less and a continuous loss position for 12 months and longer. There are 5 and 14 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 285 holdings at June 30, 2015. June 30, 2015 Less than 12 months 12 months or longer Total Temporarily Impaired Investments Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (in thousands) U.S. Government Sponsored Enterprises $ 1,997 $ 2 $ — $ — $ 1,997 $ 2 U.S. Government Agency and Sponsored Enterprises Mortgage Backed Securities 7,335 5 74,363 321 81,698 326 Privately Issued Residential Mortgage Backed Securities — — 597 17 597 17 Obligations Issued by States and Political Subdivisions — — 3,820 876 3,820 876 Other Debt Securities 399 1 1,386 114 1,785 115 Total temporarily impaired securities $ 9,731 $ 8 $ 80,166 $ 1,328 $ 89,897 $ 1,336 The following table shows the temporarily impaired securities of the Company’s available-for-sale portfolio at December 31, 2014. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for 12 months or less and a continuous loss position for 12 months and longer. There are 3 and 14 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 262 holdings at December 31, 2014. December 31, 2014 Less than 12 months 12 months or longer Total Temporarily Impaired Investments Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (in thousands) U.S. Government Sponsored Enterprises $ — $ — $ — $ — $ — $ — U.S. Government Agency and Sponsored Enterprises Mortgage Backed Securities 24,457 85 77,585 367 102,042 452 Privately Issued Residential Mortgage Backed Securities — — 678 25 678 25 Obligations Issued by States and Political Subdivisions — — 3,820 873 3,820 873 Other Debt Securities — — 1,400 100 1,400 100 Total temporarily impaired securities $ 24,457 $ 85 $ 83,483 $ 1,365 $ 107,940 $ 1,450

Investment Securities Held-to-M

Investment Securities Held-to-Maturity	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Investment Securities Held-to-Maturity	Note 3. Investment Securities Held-to-Maturity June 30, 2015 December 31, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Amortized Gross Gross Estimated (in thousands) U.S. Government Sponsored Enterprises $ 319,405 $ 3,233 $ 392 $ 322,246 $ 251,617 $ 2,707 $ 249 $ 254,075 U.S. Government Agency and Sponsored Enterprises Mortgage Backed Securities 1,364,163 10,707 7,544 1,367,326 1,155,175 11,185 6,832 1,159,528 Total $ 1,683,568 $ 13,940 $ 7,936 $ 1,689,572 $ 1,406,792 $ 13,892 $ 7,081 $ 1,413,603 Included in U.S. Government and Agency Securities are securities pledged to secure public deposits and repurchase agreements at fair value amounting to $1,062,575,000 and $868,924,000 at June 30, 2015 and December 31, 2014, respectively. Also included are securities pledged for borrowing at the Federal Home Loan Bank of Boston at fair value amounting to $411,957,000 and $458,782,000 at June 30, 2015 and December 31, 2014, respectively. At June 30, 2015 and December 31, 2014, all mortgage-backed securities are obligations of U.S. Government Agencies and Government Sponsored Enterprises. Government Sponsored Enterprises primarily refer to debt securities of Fannie Mae and Freddie Mac. The following table shows the maturity distribution of the Company’s securities held-to-maturity at June 30, 2015. Amortized Cost Fair Value ( in thousands) Within one year $ 2,854 $ 2,895 After one but within five years 1,264,143 1,268,516 After five but within ten years 406,814 408,543 More than ten years 9,757 9,618 Total $ 1,683,568 $ 1,689,572 The weighted average remaining life of investment securities held-to-maturity at June 30, 2015 was 4.5 years. Included in the weighted average remaining life calculation at June 30, 2015 were $202,373,000 of U.S. Government Sponsored Enterprises obligations that are callable at the discretion of the issuer. The actual maturities, which were used in the table above, of mortgage-backed securities, will differ from the contractual maturities, due to the ability of the issuers to prepay underlying obligations. As of June 30, 2015 and December 31, 2014, management concluded that the unrealized losses of its investment securities are temporary in nature since they are not related to the underlying credit quality of the issuers, and the Company does not intend to sell these debt securities and it is not likely that it will be required to sell these debt securities before the anticipated recovery of their remaining amortized costs. In making its other-than-temporary impairment evaluation, the Company considered the fact that the principal and interest on these securities are from issuers that are investment grade. The unrealized loss on U.S. Government Agency and Sponsored Enterprises Mortgage-Backed Securities related primarily to interest rates and not credit quality, and because the Company does not intend to sell any of these securities and it is not likely that it will be required to sell these securities before the anticipated recovery of the remaining amortized cost, the Company does not consider these investments to be other-than-temporarily impaired at June 30, 2015 and December 31, 2014. In evaluating the underlying credit quality of a security, management considers several factors such as the credit rating of the obligor and the issuer, if applicable. Internal reviews of issuer financial statements are performed as deemed necessary. The following table shows the temporarily impaired securities of the Company’s held-to-maturity portfolio at June 30, 2015. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for 12 months or less and a continuous loss position for 12 months and longer. There are 98 and 22 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 352 holdings at June 30, 2015. June 30, 2015 Less Than 12 Months 12 Months or Longer Total Temporarily Impaired Investments Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (In thousands) U.S. Government Sponsored Enterprises $ 91,968 $ 392 $ — $ — $ 91,968 $ 392 U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities 561,000 4,935 123,344 2,609 684,344 7,544 Total temporarily impaired securities $ 652,968 $ 5,327 $ 123,344 $ 2,609 $ 776,312 $ 7,936 The following table shows the temporarily impaired securities of the Company’s held-to-maturity portfolio at December 31, 2014. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for 12 months or less and a continuous loss position for 12 months and longer. There are 34 and 48 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 303 holdings at December 31, 2014. December 31, 2014 Less Than 12 Months 12 Months or Longer Total Temporarily Impaired Investments Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized (In thousands) U.S. Government Sponsored Enterprises $ 22,414 $ 25 $ 14,776 $ 224 $ 37,190 $ 249 U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities 194,119 1,678 308,526 5,154 502,645 6,832 Total temporarily impaired securities $ 216,533 $ 1,703 $ 323,302 $ 5,378 $ 539,835 $ 7,081

Allowance for Loan Losses

Allowance for Loan Losses	6 Months Ended
	Jun. 30, 2015
Receivables [Abstract]
Allowance for Loan Losses	Note 4. Allowance for Loan Losses The Company maintains an allowance for loan losses in an amount determined by management on the basis of the character of the loans, loan performance, financial condition of borrowers, the value of collateral securing loans and other relevant factors. The following table summarizes the changes in the Company’s allowance for loan losses for the periods indicated. Three months ended Six months ended June 30, June 30, 2015 2014 2015 2014 (In thousands) Allowance for loan losses, beginning of period $ 22,529 $ 21,259 $ 22,318 $ 20,941 Loans charged off (403 ) (113 ) (484 ) (542 ) Recoveries on loans previously charged-off 119 126 211 273 Net recoveries (charge-offs) (284 ) 13 (273 ) (269 ) Provision charged to expense — 450 200 1,050 Allowance for loan losses, end of period $ 22,245 $ 21,722 $ 22,245 $ 21,722 Further information pertaining to the allowance for loan losses for the three months ending June 30, 2015 follows: Construction and Land Commercial and Industrial Municipal Commercial Estate Residential Real Estate Consumer Home Equity Unallocated Total (In thousands) Allowance for loan losses: Balance at March 31, 2015 $ 1,884 $ 4,645 $ 1,373 $ 11,127 $ 799 $ 714 $ 614 $ 1,373 $ 22,529 Charge-offs — (52 ) — (298 ) — (53 ) — — (403 ) Recoveries — 56 — 2 2 59 — — 119 Provision (151 ) (221 ) (373 ) 892 (79 ) (11 ) 36 (93 ) — Ending balance at June 30, 2015 $ 1,733 $ 4,428 $ 1,000 $ 11,723 $ 722 $ 709 $ 650 $ 1,280 $ 22,245 Amount of allowance for loan losses for loans deemed to be impaired $ 12 $ 43 $ — $ 108 $ 41 $ — $ 91 $ — 295 Amount of allowance for loan losses for loans not deemed to be impaired $ 1,721 $ 4,385 $ 1,000 $ 11,615 $ 681 $ 709 $ 559 $ 1,280 $ 21,950 Loans: Ending balance $ 26,521 $ 291,142 $ 87,241 $ 713,770 $ 248,103 $ 10,646 $ 167,271 $ — $ 1,544,694 Loans deemed to be impaired $ 101 $ 595 $ — $ 1,705 $ 941 $ — $ 91 $ — $ 3,433 Loans not deemed to be impaired $ 26,420 $ 290,547 $ 87,241 $ 712,065 $ 247,162 $ 10,646 $ 167,180 $ — $ 1,541,261 Further information pertaining to the allowance for loan losses for the six months ending June 30, 2015 follows: Construction and Land Commercial and Industrial Municipal Commercial Estate Residential Real Estate Consumer Home Equity Unallocated Total (In thousands) Allowance for loan losses: Balance at December 31, 2014 $ 1,592 $ 4,758 $ 1,488 $ 11,199 $ 775 $ 810 $ 599 $ 1,097 $ 22,318 Charge-offs — (52 ) — (298 ) — (134 ) — — (484 ) Recoveries — 71 — 4 4 132 — — 211 Provision 141 (349 ) (488 ) 818 (57 ) (99 ) 51 183 200 Ending balance at June 30, 2015 $ 1,733 $ 4,428 $ 1,000 $ 11,723 $ 722 $ 709 $ 650 $ 1,280 $ 22,245 Amount of allowance for loan losses for loans deemed to be impaired $ 12 $ 43 $ — $ 108 $ 41 $ — $ 91 $ — 295 Amount of allowance for loan losses for loans not deemed to be impaired $ 1,721 $ 4,385 $ 1,000 $ 11,615 $ 681 $ 709 $ 559 $ 1,280 $ 21,950 Loans: Ending balance $ 26,521 $ 291,142 $ 87,241 $ 713,770 $ 248,103 $ 10,646 $ 167,271 $ — $ 1,544,694 Loans deemed to be impaired $ 101 $ 595 $ — $ 1,705 $ 941 $ — $ 91 $ — $ 3,433 Loans not deemed to be impaired $ 26,420 $ 290,547 $ 87,241 $ 712,065 $ 247,162 $ 10,646 $ 167,180 $ — $ 1,541,261 Further information pertaining to the allowance for loan losses for the three months ending June 30, 2014 follows: Construction Commercial Municipal Commercial Residential Consumer Home Unallocated Total (In thousands) Allowance for loan losses: Balance at March 31, 2014 $ 1,825 $ 2,593 $ 804 $ 11,567 $ 1,873 $ 425 $ 902 $ 1,270 $ 21,259 Charge-offs — (14 ) — — — (99 ) — — (113 ) Recoveries — 24 — 2 15 84 1 — 126 Provision 220 (173 ) (41 ) 128 39 18 12 247 450 Ending balance at June 30, 2014 $ 2,045 $ 2,430 $ 763 $ 11,697 $ 1,927 $ 428 $ 915 $ 1,517 $ 21,722 Amount of allowance for loan losses for loans deemed to be impaired $ 273 $ 353 $ — $ 359 $ 160 $ — $ 93 $ — 1. 238 Amount of allowance for loan losses for loans not deemed to be impaired $ 1,772 $ 2,077 $ 763 $ 11,338 $ 1,767 $ 428 $ 822 $ 1,517 $ 20,484 Loans: Ending balance $ 25,861 $ 73,204 $ 31,982 $ 750,445 $ 282,468 $ 9,649 $ 140,616 $ — $ 1,314,225 Loans deemed to be impaired $ 356 $ 1,093 $ — $ 4,775 $ 1,559 $ — $ 93 $ — $ 7,876 Loans not deemed to be impaired $ 25,505 $ 72,111 $ 31,982 $ 745,670 $ 280,909 $ 9,649 $ 140,523 $ — $ 1,306,349 Further information pertaining to the allowance for loan losses for the six months ending June 30, 2014 follows: Construction Commercial Municipal Commercial Residential Consumer Home Unallocated Total (In thousands) Allowance for loan losses: Balance at December 31, 2013 $ 2,174 $ 2,617 $ 655 $ 10,935 $ 2,006 $ 432 $ 959 $ 1,163 $ 20,941 Charge-offs (250 ) (14 ) — — — (278 ) — — (542 ) Recoveries — 48 — 4 20 200 1 — 273 Provision 121 (221 ) 108 758 (99 ) 74 (45 ) 354 1,050 Ending balance at June 30, 2014 $ 2,045 $ 2,430 $ 763 $ 11,697 $ 1,927 $ 428 $ 915 $ 1,517 $ 21,722 Amount of allowance for loan losses for loans deemed to be impaired $ 273 $ 353 $ — $ 359 $ 160 $ — $ 93 $ — 1. 238 Amount of allowance for loan losses for loans not deemed to be impaired $ 1,772 $ 2,077 $ 763 $ 11,338 $ 1,767 $ 428 $ 822 $ 1,517 $ 20,484 Loans: Ending balance $ 25,861 $ 73,204 $ 31,982 $ 750,445 $ 282,468 $ 9,649 $ 140,616 $ — $ 1,314,225 Loans deemed to be impaired $ 356 $ 1,093 $ — $ 4,775 $ 1,559 $ — $ 93 $ — $ 7,876 Loans not deemed to be impaired $ 25,505 $ 72,111 $ 31,982 $ 745,670 $ 280,909 $ 9,649 $ 140,523 $ — $ 1,306,349 The Company utilizes a six grade internal loan rating system for commercial real estate, construction and commercial loans as follows: Loans rated 1-3 (Pass): Loans in this category are considered “pass” rated loans with low to average risk. Loans rated 4 (Monitor): These loans represent classified loans that management is closely monitoring for credit quality. These loans have had or may have minor credit quality deterioration as of June 30, 2015 and December 31, 2014. Loans rated 5 (Substandard): Substandard loans represent classified loans that management is closely monitoring for credit quality. These loans have had more significant credit quality deterioration as of June 30, 2015 and December 31, 2014. Loans rated 6 (Doubtful): Doubtful loans represent classified loans that management is closely monitoring for credit quality. These loans had more significant credit quality deterioration as of June 30, 2015 and December 31, 2014 and are doubtful for full collection. Impaired: Impaired loans represent classified loans that management is closely monitoring for credit quality. A loan is classified as impaired when it is probable that the Company will be unable to collect all amounts due. The following table presents the Company’s loans by risk rating at June 30, 2015. Construction and Land Development Commercial and Industrial Municipal Commercial Estate (In thousands) Grade: 1-3 (Pass) $ 19,396 $ 290,547 $ 87,241 $ 711,449 4 (Monitor) 7,024 — — 616 5 (Substandard) — — — — 6 (Doubtful) — — — — Impaired 101 595 — 1,705 Total $ 26,521 $ 291,142 $ 87,241 $ 713,770 The following table presents the Company’s loans by risk rating at December 31, 2014. Construction Commercial Municipal Commercial (In thousands) Grade: 1-3 (Pass) $ 15,515 $ 148,407 $ 41,850 $ 691,322 4 (Monitor) 7,126 472 — 633 5 (Substandard) — — — — 6 (Doubtful) — — — — Impaired 103 853 — 4,317 Total $ 22,744 $ 149,732 $ 41,850 $ 696,272 During the second quarter of 2015, the Company enhanced its approach to the development of the historical loss factors on certain loans within the portfolio. This was done in response to the changing composition of the portfolio. In recent quarters, the Company has increased its exposure to larger loans to larger institutions which receive credit ratings. The Company currently has limited loss experience with these types of loans. There is, however, a great deal of default and loss data available on these types of loans from the credit rating agencies. As of June 30, 2015, the Company incorporated this information into the development of the historical loss rates for these loan types. Credit ratings issued by national organizations were utilized as credit quality indicators as presented in the following table at June 30, 2015. Commercial and Industrial Municipal Commercial Estate (In thousands) Credit Rating: Aaa – Aa3 $ 135,059 $ 60,483 $ 8,014 A1 – A3 80,385 7,820 131,641 Baa1 – Baa3 — 9,035 154,699 Ba2 — 4,480 — Total $ 215,444 $ 81,818 $ 294,354 The Company utilized payment performance as credit quality indicators for residential real estate, consumer and overdrafts, and the home equity portfolio. The indicators are depicted in the table “aging of past due loans,” below. Further information pertaining to the allowance for loan losses at June 30, 2015 follows: Accruing 30-89 Days Past Due Non Accrual Accruing Greater Than 90 Days Total Past Due Current Loans Total (In thousands) Construction and land development $ — $ 101 $ — $ 101 $ 26,420 $ 26,521 Commercial and industrial — 122 — 122 291,020 291,142 Municipal — — — — 87,241 87,241 Commercial real estate 926 186 — 1,112 712,658 713,770 Residential real estate 927 1,136 — 2,063 246,040 248,103 Consumer and overdrafts 8 3 — 11 10,635 10,646 Home equity 407 638 — 1,045 166,226 167,271 Total $ 2,268 $ 2,186 $ — $ 4,454 $ 1,540,240 $ 1,544,694 Further information pertaining to the allowance for loan losses at December 31, 2014 follows: Accruing Non Accrual Accruing Total Current Loans Total (In thousands) Construction and land development $ — $ 103 $ — $ 103 $ 22,641 $ 22,744 Commercial and industrial 905 157 — 1,062 148,670 149,732 Municipal — — — — 41,850 41,850 Commercial real estate 1,046 2,781 — 3,827 692,445 696,272 Residential real estate 632 846 — 1,478 255,827 257,305 Consumer and overdrafts 6 5 — 11 12,177 12,188 Home equity 576 254 — 830 150,445 151,275 Total $ 3,165 $ 4,146 $ — $ 7,311 $ 1,324,055 $ 1,331,366 A loan is impaired when, based on current information and events, it is probable that a creditor will be unable to collect all amounts due according to the contractual terms of the loan agreement. When a loan is impaired, the Company measures impairment based on the present value of expected future cash flows discounted at the loan’s effective interest rate, except that as a practical expedient, the Company measures impairment based on a loan’s observable market price, or the fair value of the collateral if the loan is collateral dependent. Loans are charged-off when management believes that the collectability of the loan’s principal is not probable. The specific factors that management considers in making the determination that the collectability of the loan’s principal is not probable include; the delinquency status of the loan, the fair value of the collateral, if secured, and the financial strength of the borrower and/or guarantors. For collateral dependent loans, the amount of the recorded investment in a loan that exceeds the fair value of the collateral is charged-off against the allowance for loan losses in lieu of an allocation of a specific allowance amount when such an amount has been identified definitively as uncollectible. The Company’s policy for recognizing interest income on impaired loans is contained within Note 1 of the consolidated financial statements contained in the Company’s Annual Report for the fiscal year ended December 31, 2014. The following is information pertaining to impaired loans for June 30, 2015: Carrying Value Unpaid Principal Balance Required Reserve Average Ending 6/30/15 Interest Income Recognized For 3 Months Average Ending 6/30/15 Interest Income Recognized For 6 Months (Dollars in thousands) With no required reserve recorded: Construction and land development $ — $ — $ — $ — $ — $ — $ — Commercial and industrial 32 32 — 47 — 40 — Municipal — — — — — — — Commercial real estate — — — 196 — 280 — Residential real estate 126 210 — 129 2 131 4 Consumer — — — — — — — Home equity — — — — — — — Total $ 158 $ 242 $ — $ 372 $ 2 $ 451 $ 4 With required reserve recorded: Construction and land development $ 101 $ 108 $ 12 $ 102 $ — $ 102 $ — Commercial and industrial 563 765 43 644 5 722 11 Municipal — — — — — — — Commercial real estate 1,705 1,801 108 2,809 17 3,286 33 Residential real estate 815 815 41 817 1 820 7 Consumer — — — — — — — Home equity 91 91 91 91 — 92 — Total $ 3,275 $ 3,580 $ 295 $ 4,463 $ 23 $ 5,022 $ 51 Total: Construction and land development $ 101 $ 108 $ 12 $ 102 $ — $ 102 $ — Commercial and industrial 595 797 43 691 5 762 11 Municipal — — — — — — — Commercial real estate 1,705 1,801 108 3,005 17 3,566 33 Residential real estate 941 1,025 41 946 3 951 11 Consumer — — — — — — — Home equity 91 91 91 91 — 92 — Total $ 3,433 $ 3,822 $ 295 $ 4,835 $ 25 $ 5,473 $ 55 The following is information pertaining to impaired loans for June 30, 2014: Carrying Value Unpaid Required Average Interest Average Interest (Dollars in thousands) With no required reserve recorded: Construction and land development $ — $ — $ — $ 188 $ — $ 321 $ — Commercial and industrial 11 42 — 11 — 71 — Commercial real estate 400 400 — 100 — 80 — Residential real estate 70 70 — 31 — 104 — Consumer — — — — — — — Home equity — — — — — — — Total $ 481 $ 512 $ — $ 330 $ — $ 576 $ — With required reserve recorded: Construction and land development $ 356 $ 3,400 $ 273 $ 169 $ — $ 143 $ — Commercial and industrial 1,082 1,332 353 1,095 8 1,104 19 Commercial real estate 4,375 4,466 359 4,391 36 4,405 74 Residential real estate 1,489 1,684 160 1,106 3 1,039 5 Consumer — — — — — — — Home equity 93 93 93 94 — 94 — Total $ 7,395 $ 10,975 $ 1,238 $ 6,855 $ 47 $ 6,785 $ 98 Total: Construction and land development $ 356 $ 3,400 $ 273 $ 357 $ — $ 465 $ — Commercial and industrial 1,093 1,374 353 1,106 8 1,175 19 Commercial real estate 4,775 4,866 359 4,491 36 4,485 74 Residential real estate 1,559 1,754 160 1,137 3 1,143 5 Consumer — — — — — — — Home equity 93 93 93 94 — 94 — Total $ 7,876 $ 11,487 $ 1,238 $ 7,185 $ 47 $ 7,362 $ 98 There were no troubled debt restructurings occurring during the six month periods ended June 30, 2015 or June 30, 2014.

Reclassifications Out of Accumu

Reclassifications Out of Accumulated Other Comprehensive Income	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Reclassifications Out of Accumulated Other Comprehensive Income	Note 5. Reclassifications Out of Accumulated Other Comprehensive Income Amount Reclassified from Accumulated Other Comprehensive Income Details about Accumulated Other Comprehensive Income Components Three Months Ended June 30, 2015 Three Months Ended June 30, 2014 Affected Line Item in the Statement Where Net Income is Presented (in thousands) Unrealized gains and losses on available-for-sale securities $ 118 $ — Net gains on sales of securities (47 ) — Provision for income taxes $ 71 $ — Net income Accretion of unrealized losses transferred $ 1,576 $ 1,286 Interest on securities held-to-maturity (549 ) (478 ) Provision for income taxes $ 1,027 $ 808 Net income Amortization of defined benefit pension items Prior-service costs $ (3 )(b) $ (3 )(b) Salaries and employee benefits Actuarial gains (losses) (352 )(b) (91 )(b) Salaries and employee benefits Total before tax (355 ) (94 ) Income before taxes Tax (expense) or benefit 142 38 Provision for income taxes Net of tax $ (213 ) $ (56 ) Net income Total reclassifications for the period $ 885 $ 752 Net income, net of tax Details about Accumulated Other Comprehensive Income Components Six Months Ended Six Months Ended Affected Line Item in the Statement Where Net Income is Presented (in thousands) Unrealized gains and losses on available-for-sale securities $ 118 $ — Net gains on sales of securities (47 ) — Provision for income taxes $ 71 $ — Net income Accretion of unrealized losses transferred $ 2,705 $ 2,793 Interest on securities held-to-maturity (943 ) (1,061 ) Provision for income taxes $ 1,762 $ 1,732 Net income Amortization of defined benefit pension items Prior-service costs $ (6 )(b) $ (5 )(b) Salaries and employee benefits Actuarial gains (losses) (704 )(b) (183 )(b) Salaries and employee benefits Total before tax (710 ) (188 ) Income before taxes Tax (expense) or benefit 284 75 Provision for income taxes Net of tax $ (426 ) $ (113 ) Net income Total reclassifications for the period $ 1,407 $ 1,619 Net income, net of tax (a) Amount in parentheses indicate debits to profit/loss. (b) These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see employee benefits footnote (Note 8) for additional details).

Earnings per Share ("EPS")

Earnings per Share ("EPS")	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Earnings per Share ("EPS")	Note 6. Earnings per Share (“EPS”) Class A and Class B shares participate equally in undistributed earnings. Under the Company’s Articles of Organization, the holders of Class A Common Stock are entitled to receive dividends per share equal to at least 200% of dividends paid, if any, from time to time, on each share of Class B Common Stock. Diluted EPS includes the dilutive effect of common stock equivalents; basic EPS excludes all common stock equivalents. The only common stock equivalents for the Company are the stock options discussed below. The dilutive effect of these stock options for three and six months ended June 30, 2014 was an increase of 1,327 and 1,452 shares, respectively. There were no stock options outstanding during the six months ended June 30, 2015. The following table is a reconciliation of basic EPS and diluted EPS for the three and six months ended June 30, Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Basic EPS Computation: Numerator: Net income, Class A $ 4,654 $ 4,394 $ 8,549 $ 8,259 Net income, Class B 1,271 1,205 2,335 2,272 Denominator: Weighted average shares outstanding, Class A 3,600,729 3,589,125 3,600,729 3,585,773 Weighted average shares outstanding, Class B 1,967,180 1,967,580 1,967,180 1,970,880 Basic EPS, Class A $ 1.29 $ 1.22 $ 2.37 $ 2.30 Basic EPS, Class B 0.65 0.61 1.19 1.15 Diluted EPS Computation: Numerator: Net income, Class A $ 4,654 $ 4,394 $ 8,549 $ 8,259 Net income, Class B 1,271 1,205 2,335 2,272 Total net income, for diluted EPS, Class A computation 5,925 5,599 10,884 10,531 Denominator: Weighted average shares outstanding, basic, Class A 3,600,729 3,589,125 3,600,729 3,585,773 Weighted average shares outstanding, Class B 1,967,180 1,967,580 1,967,180 1,970,880 Dilutive effect of Class A stock options — 1,327 — 1,452 Weighted average shares outstanding diluted, Class A 5,567,909 5,558,032 5,567,909 5,558,105 Weighted average shares outstanding, Class B 1,967,180 1,967,580 1,967,180 1,970,880 Diluted EPS, Class A $ 1.06 $ 1.01 $ 1.95 $ 1.89 Diluted EPS, Class B 0.65 0.61 1.19 1.15

Employee Benefits

Employee Benefits	6 Months Ended
	Jun. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Employee Benefits	Note 7. Employee Benefits The Company provides pension benefits to its employees under a noncontributory, defined benefit plan which is funded on a current basis in compliance with the requirements of the Employee Retirement Income Security Act of 1974 (“ERISA”) and recognizes costs over the estimated employee service period. The Company also has a Supplemental Executive Insurance/Retirement Plan (the “Supplemental Plan”) which is limited to certain officers and employees of the Company. The Supplemental Plan is accrued on a current basis and recognizes costs over the estimated employee service period. Executive officers of the Company and its subsidiaries who have at least one year of service may participate in the Supplemental Plan. The Supplemental Plan is voluntary and participants are required to contribute to its cost. Life insurance policies, which are owned by the Company, are purchased covering the lives of each participant. Components of Net Periodic Benefit Cost (Credit) for the Three Months Ended June 30, Pension Benefits Supplemental Insurance/ Retirement Plan 2015 2014 2015 2014 (In thousands) Service cost $ 336 $ 258 $ 397 $ 389 Interest 394 367 341 331 Expected return on plan assets (688 ) (636 ) — — Recognized prior service cost (benefit) (26 ) (26 ) 29 29 Recognized net actuarial losses 204 3 149 88 Net periodic benefit (credit) cost $ 220 $ (34 ) $ 916 $ 837 Components of Net Periodic Benefit Cost (Credit) for the Six Months Ended June 30, Pension Benefits Supplemental Insurance/ Retirement Plan 2015 2014 2015 2014 (In thousands) Service cost $ 672 $ 516 $ 794 $ 778 Interest 788 734 682 662 Expected return on plan assets (1,376 ) (1,272 ) — — Recognized prior service cost (benefit) (52 ) (52 ) 58 58 Recognized net actuarial losses 407 6 299 176 Net periodic benefit (credit) cost $ 439 $ (68 ) $ 1,833 $ 1,674 Contributions The company intends to contribute $2,000,000 to the Pension Plan in 2015. As of June 30, 2015, $1,000,000 has been contributed.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 8. Fair Value Measurements The Company follows FASB ASC 820-10, Fair Value Measurements and Disclosures Level I – Quoted prices are available in active markets for identical assets or liabilities as of the reported date. The type of financial instruments included in Level I are highly liquid cash instruments with quoted prices such as G-7 government, agency securities, listed equities and money market securities, as well as listed derivative instruments. Level II – Pricing inputs are other than quoted prices in active markets, which are either directly or indirectly observable as of the reported date. The nature of these financial instruments include cash instruments for which quoted prices are available but traded less frequently, derivative instruments whose fair value have been derived using a model where inputs to the model are directly observable in the market, or can be derived principally from or corroborated by observable market data, and instruments that are fair valued using other financial instruments, the parameters of which can be directly observed. Instruments which are generally included in this category are corporate bonds and loans, mortgage whole loans, municipal bonds and OTC derivatives. Level III – Instruments that have little to no pricing observability as of the reported date. These financial instruments do not have two-way markets and are measured using management’s best estimate of fair value, where the inputs into the determination of fair value require significant management judgment or estimation. Instruments that are included in this category generally include certain commercial mortgage loans, certain private equity investments, distressed debt, non-investment grade residual interests in securitizations, as well as certain highly structured OTC derivative contracts. The results of the fair value hierarchy as of June 30, 2015, are as follows: Financial Instruments Measured at Fair Value on a Recurring Basis: Securities AFS Fair Value Measurements Using Carrying Quoted Prices In Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) (In thousands) U.S. Treasury $ 1,997 $ — $ 1,997 $ — SBA Backed Securities 6,494 — 6,494 — U.S. Government Agency and Sponsored Mortgage Backed Securities 273,563 — 273,563 — Privately Issued Residential Mortgage Backed Securities 1,641 — 1,641 — Obligations Issued by States and Political Subdivisions 152,541 — — 152,541 Other Debt Securities 3,499 — 3,499 — Equity Securities 324 287 — 37 Total $ 440,059 $ 287 $ 287,194 $ 152,578 Financial Instruments Measured at Fair Value on a Non-recurring Basis: Impaired Loans 1,159 — — 1,159 Other Real Estate Owned 1,916 1,916 Impaired loan balances represent those collateral dependent loans where management has estimated the credit loss by comparing the loan’s carrying value against the expected realizable fair value of the collateral. Fair value is generally determined through a review process that includes independent appraisals, discounted cash flows, or other external assessments of the underlying collateral, which generally include various Level 3 inputs which are not identifiable. The Company discounts the fair values, as appropriate, based on management’s observations of the local real estate market for loans in this category. Appraisals, discounted cash flows and real estate tax assessments are reviewed quarterly. There is no specific policy regarding how frequently appraisals will be updated. Adjustments are made to appraisals and real estate tax assessments based on management’s estimate of changes in real estate values. Within the past twelve months there have been no updated appraisals, however, all impaired loans have been reviewed during the past quarter using either a discounted cash flow analysis, appraisal of collateral or other type of real estate tax assessment. The types of adjustments that are made to specific provisions (credits) relate to impaired loans recognized for the three and six-month periods ended June 30, 2015 amounted to $558,000 and $594,000, respectively. There were no transfers between level 1, 2 and 3 for the six months ended June 30, 2015. There were no liabilities measured at fair value on a recurring or nonrecurring basis during the six month period ended June 30, 2015. The following table presents additional information about assets measured at fair value on a recurring and nonrecurring basis for which the Company has utilized Level 3 inputs to determine fair value (dollars in thousands). Management continues to monitor the assumptions used to value the assets listed below. Asset Fair Value Valuation Technique Unobservable Input Unobservable Input Value or Range Securities AFS (4) $ 152,578 Discounted cash flow Discount rate 0%-1% (3) Impaired Loans 1,159 Appraisal of collateral (1) Appraisal adjustments (2) 0%-30% discount Other Real Estate Owned 1,916 Appraisal (1) Appraisal adjustments (2) 0%-30% discount (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various Level 3 inputs which are not identifiable. (2) Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated expenses. (3) Weighted averages. (4) Municipal securities generally have maturities of one year or less and, therefore, the amortized cost equates to the fair value. The changes in Level 3 securities for the six-month period ended June 30, 2015 are shown in the table below: Auction Securities Obligations Equity Total (In thousands) Balance at December 31, 2014 $ 3,820 $ 92,964 $ 102 $ 96,886 Purchases — 113,179 — 113,179 Maturities and calls — (57,411 ) (65 ) (57,476 ) Amortization — (11 ) — (11 ) Changes in fair value — — — — Balance at June 30, 2015 $ 3,820 $ 148,721 $ 37 $ 152,578 The amortized cost of Level 3 securities was $153,454,000 at June 30, 2015 with an unrealized loss of $876,000. The securities in this category are generally equity investments, municipal securities with no readily determinable fair value or failed auction rate securities. Management evaluated the fair value of these securities based on an evaluation of the underlying issuer, prevailing rates and market liquidity. The changes in Level 3 securities for the six-month period ended June 30, 2014, are shown in the table below: Auction Securities Obligations Equity Total (In thousands) Balance at December 31, 2013 $ 3,820 $ 32,487 $ 290 $ 36,597 Purchases — 51,471 — 51,471 Maturities and calls — (27,282 ) (79 ) (27,361 ) Amortization — (2 ) — (2 ) Changes in fair value — — — — Balance at June 30, 2014 $ 3,820 $ 56,674 $ 211 $ 60,705 The amortized cost of Level 3 securities was $61,577,000 at June 30, 2014 with an unrealized loss of $872,000. The securities in this category are generally equity investments, municipal securities with no readily determinable fair value or failed auction rate securities. Management evaluated the fair value of these securities based on an evaluation of the underlying issuer, prevailing rates and market liquidity. The results of the fair value hierarchy as of December 31, 2014, are as follows: Financial Instruments Measured at Fair Value on a Recurring Basis: Securities AFS Fair Value Measurements Using Carrying Quoted Prices In Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) (In thousands) U.S. Treasury $ 2,000 $ — $ 2,000 $ — U.S. Government Sponsored Enterprises — — — — SBA Backed Securities 6,717 — 6,717 — U.S. Government Agency and Sponsored Mortgage Backed Securities 337,093 — 337,093 — Privately Issued Residential Mortgage Backed Securities 1,874 — 1,874 — Obligations Issued by States and Political Subdivisions 96,784 — — 96,784 Other Debt Securities 3,524 — 3,524 — Equity Securities 398 296 — 102 Total $ 448,390 $ 296 $ 351,208 $ 96,886 Financial Instruments Measured at Fair Value on a Non-recurring Basis: Impaired Loans 3,410 — — 3,410 Impaired loan balances represent those collateral dependent loans where management has estimated the credit loss by comparing the loan’s carrying value against the expected realizable fair value of the collateral. Fair value is generally determined through a review process that includes independent appraisals, discounted cash flows, or other external assessments of the underlying collateral, which generally include various Level 3 inputs which are not identifiable. The Company discounts the fair values, as appropriate, based on management’s observations of the local real estate market for loans in this category. Appraisals, discounted cash flows and real estate tax assessments are reviewed quarterly. There is no specific policy regarding how frequently appraisals will be updated. Adjustments are made to appraisals and real estate tax assessments based on management’s estimate of changes in real estate values. Within the past twelve months there have been no updated appraisals, however, all impaired loans have been reviewed during the past quarter using either a discounted cash flow analysis, appraisal of collateral or other type of real estate tax assessment. The types of adjustments that are made to specific provisions (credits) relate to impaired loans recognized for the period ended 2014 for the estimated credit loss amounted to $947,000. There were no transfers between level 1, 2 and 3 for the year ended December 31, 2014. There were no liabilities measured at fair value on a recurring or nonrecurring basis during the year ended December 31, 2014. The following table presents additional information about assets measured at fair value on a recurring and nonrecurring basis for which the Company has utilized Level 3 inputs to determine fair value (dollars in thousands). Management continues to monitor the assumptions used to value the assets listed below. Asset Fair Valuation Technique Unobservable Input Unobservable Input Value or Range Securities AFS (4) $ 96,886 Discounted cash flow Discount rate 0%-1% (3) Impaired Loans 3,410 Appraisal of collateral (1) Appraisal adjustments (2) 0%-30% discount (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various Level 3 inputs which are not identifiable. (2) Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated expenses. (3) Weighted averages (4) Municipal securities generally have maturities of one year or less and, therefore, the amortized cost equates to the fair value.

Fair Values of Financial Instru

Fair Values of Financial Instruments	6 Months Ended
	Jun. 30, 2015
Investments, All Other Investments [Abstract]
Fair Values of Financial Instruments	Note 9. Fair Values of Financial Instruments The following methods and assumptions were used by the Company in estimating fair values of its financial instruments. Excluded from this disclosure are all nonfinancial instruments. Accordingly, the aggregate fair value amounts presented do not represent the underlying value of the Company. The assumptions used below are expected to approximate those that market participants would use in valuing these financial instruments. Fair value estimates are made at a specific point in time, based on available market information and judgments about the financial instrument, including estimates of timing, amount of expected future cash flows and the credit standing of the issuer. Such estimates do not consider the tax impact of the realization of unrealized gains or losses. In some cases, the fair value estimates cannot be substantiated by comparison to independent markets. In addition, the disclosed fair value may not be realized in the immediate settlement of the financial instrument. Care should be exercised in deriving conclusions about our business, its value or financial position based on the fair value information of financial instruments presented below. Securities held-to-maturity: The fair values of these securities were based on quoted market prices, where available, as provided by third-party investment portfolio pricing vendors. If quoted market prices were not available, fair values provided by the vendors were based on quoted market prices of comparable instruments in active markets and/or based on a matrix pricing methodology which employs The Bond Market Association’s standard calculations for cash flow and price/yield analysis, live benchmark bond pricing and terms/condition data available from major pricing sources. Management regards the inputs and methods used by third party pricing vendors to be “Level 2 inputs and methods” as defined in the “fair value hierarchy” provided by FASB. Loans: For variable-rate loans, that reprice frequently and with no significant change in credit risk, fair values are based on carrying amounts. The fair value of other loans is estimated using discounted cash flow analysis, based on interest rates currently being offered for loans with similar terms to borrowers of similar credit quality. Incremental credit risk for nonperforming loans has been considered. Time deposits: The fair value of time deposits was estimated using a discounted cash flow approach that applies prevailing market interest rates for similar maturity instruments. The fair values of the Company’s time deposit liabilities do not take into consideration the value of the Company’s long-term relationships with depositors, which may have significant value. Other borrowed funds: The fair value of other borrowed funds is based on the discounted value of contractual cash flows. The discount rate used is estimated based on the rates currently offered for other borrowed funds of similar remaining maturities. Subordinated debentures: The fair value of subordinated debentures is based on the discounted value of contractual cash flows. The discount rate used is estimated based on the rates currently offered for other subordinated debentures of similar remaining maturities. The following presents (in thousands) the carrying amount, estimated fair value, and placement in the fair value hierarchy of the Company’s financial instruments as of June 30, 2015 and December 31, 2014. This table excludes financial instruments for which the carrying amount approximates fair value. Financial assets for which the fair value approximates carrying value include cash and cash equivalents, short-term investments, FHLBB stock and accrued interest receivable. Financial liabilities for which the fair value approximates carrying value include non-maturity deposits, short-term borrowings and accrued interest payable. Fair Value Measurements Carrying Estimated Level 1 Level 2 Level 3 (In thousands) June 30, 2015 Financial assets: Securities held-to-maturity $ 1,683,568 $ 1,689,572 $ — $ 1,689,572 $ — Loans (1) 1,522,449 1,503,326 — — 1,503,326 Financial liabilities: Time deposits 383,284 387,675 — 387,675 — Other borrowed funds 485,500 487,271 — 487,271 — Subordinated debentures 36,083 36,083 — — 36,083 December 31, 2014 Financial assets: Securities held-to-maturity 1,406,792 1,413,603 — 1,413,603 — Loans (1) 1,309,048 1,291,550 — — 1,291,550 Financial liabilities: Time deposits 383,145 387,919 — 387,919 — Other borrowed funds 395,500 400,196 — 400,196 — Subordinated debentures 36,083 36,083 — — 36,083 (1) Comprised of loans (including collateral dependent impaired loans), net of deferred loan costs and the allowance for loan losses.

Recent Accounting Developments

Recent Accounting Developments	6 Months Ended
	Jun. 30, 2015
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Developments	Note 10. Recent Accounting Developments In November 2014, the FASB issued ASU 2014-17, “Business Combinations”. (Topic 805): Pushdown Accounting (a consensus of the FASB Emerging Issues Task Force). In January 2015, the FASB issued ASU 2015-01, “Income Statement-Extraordinary and Unusual” (Subtopic 225-20): Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary Items In April 2015, the FASB issued ASU 2015-04, “Compensation-Retirement Benefits” (Topic 715): Practical Expedient for the Measurement Date of an Employer’s Defined Benefit Obligation and Plan Assets.

Securities Available-for-Sale (

Securities Available-for-Sale (Tables)	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Summary of Securities Available-for-Sale	June 30, 2015 December 31, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value (in thousands) U.S. Treasury $ 1,999 $ — $ 2 $ 1,997 $ 1,999 $ 1 $ — $ 2,000 Small Business Administration 6,446 48 — 6,494 6,684 33 — 6,717 U.S. Government Agency and Sponsored Enterprises Mortgage Backed Securities 272,775 1,114 326 273,563 336,158 1,387 452 337,093 Privately Issued Residential Mortgage Backed Securities 1,654 4 17 1,641 1,894 5 25 1,874 Obligations Issued by States and Political Subdivisions 153,417 — 876 152,541 97,657 — 873 96,784 Other Debt Securities 3,600 14 115 3,499 3,600 24 100 3,524 Equity Securities 153 171 — 324 218 180 — 398 Total $ 440,044 $ 1,351 $ 1,336 $ 440,059 $ 448,210 $ 1,630 $ 1,450 $ 448,390
Estimated Maturity Distribution of Securities Available-for-Sale	The following table shows the maturity distribution of the Company’s securities available-for-sale at June 30, 2015. Amortized Cost Fair Value (in thousands) Within one year $ 147,326 $ 147,327 After one but within five years 161,584 162,236 After five but within ten years 121,460 121,600 More than 10 years 8,021 7,187 Non-maturing 1,653 1,709 Total $ 440,044 $ 440,059
Continuous Unrealized Loss Position for 12 Months or Less and 12 Months or Longer	The following table shows the temporarily impaired securities of the Company’s available-for-sale portfolio at June 30, 2015. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for 12 months or less and a continuous loss position for 12 months and longer. There are 5 and 14 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 285 holdings at June 30, 2015. June 30, 2015 Less than 12 months 12 months or longer Total Temporarily Impaired Investments Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (in thousands) U.S. Government Sponsored Enterprises $ 1,997 $ 2 $ — $ — $ 1,997 $ 2 U.S. Government Agency and Sponsored Enterprises Mortgage Backed Securities 7,335 5 74,363 321 81,698 326 Privately Issued Residential Mortgage Backed Securities — — 597 17 597 17 Obligations Issued by States and Political Subdivisions — — 3,820 876 3,820 876 Other Debt Securities 399 1 1,386 114 1,785 115 Total temporarily impaired securities $ 9,731 $ 8 $ 80,166 $ 1,328 $ 89,897 $ 1,336 The following table shows the temporarily impaired securities of the Company’s available-for-sale portfolio at December 31, 2014. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for 12 months or less and a continuous loss position for 12 months and longer. There are 3 and 14 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 262 holdings at December 31, 2014. December 31, 2014 Less than 12 months 12 months or longer Total Temporarily Impaired Investments Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (in thousands) U.S. Government Sponsored Enterprises $ — $ — $ — $ — $ — $ — U.S. Government Agency and Sponsored Enterprises Mortgage Backed Securities 24,457 85 77,585 367 102,042 452 Privately Issued Residential Mortgage Backed Securities — — 678 25 678 25 Obligations Issued by States and Political Subdivisions — — 3,820 873 3,820 873 Other Debt Securities — — 1,400 100 1,400 100 Total temporarily impaired securities $ 24,457 $ 85 $ 83,483 $ 1,365 $ 107,940 $ 1,450

Investment Securities Held-to20

Investment Securities Held-to-Maturity (Tables)	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Summary of Held-to-Maturity Securities	June 30, 2015 December 31, 2014 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimated Fair Value Amortized Gross Gross Estimated (in thousands) U.S. Government Sponsored Enterprises $ 319,405 $ 3,233 $ 392 $ 322,246 $ 251,617 $ 2,707 $ 249 $ 254,075 U.S. Government Agency and Sponsored Enterprises Mortgage Backed Securities 1,364,163 10,707 7,544 1,367,326 1,155,175 11,185 6,832 1,159,528 Total $ 1,683,568 $ 13,940 $ 7,936 $ 1,689,572 $ 1,406,792 $ 13,892 $ 7,081 $ 1,413,603
Company's Securities Held-to-Maturity	The following table shows the maturity distribution of the Company’s securities held-to-maturity at June 30, 2015. Amortized Cost Fair Value ( in thousands) Within one year $ 2,854 $ 2,895 After one but within five years 1,264,143 1,268,516 After five but within ten years 406,814 408,543 More than ten years 9,757 9,618 Total $ 1,683,568 $ 1,689,572
Unrealized Market Loss of Securities	The following table shows the temporarily impaired securities of the Company’s held-to-maturity portfolio at June 30, 2015. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for 12 months or less and a continuous loss position for 12 months and longer. There are 98 and 22 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 352 holdings at June 30, 2015. June 30, 2015 Less Than 12 Months 12 Months or Longer Total Temporarily Impaired Investments Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses (In thousands) U.S. Government Sponsored Enterprises $ 91,968 $ 392 $ — $ — $ 91,968 $ 392 U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities 561,000 4,935 123,344 2,609 684,344 7,544 Total temporarily impaired securities $ 652,968 $ 5,327 $ 123,344 $ 2,609 $ 776,312 $ 7,936 The following table shows the temporarily impaired securities of the Company’s held-to-maturity portfolio at December 31, 2014. This table shows the unrealized market loss of securities that have been in a continuous unrealized loss position for 12 months or less and a continuous loss position for 12 months and longer. There are 34 and 48 securities that are temporarily impaired for less than 12 months and for 12 months or longer, respectively, out of a total of 303 holdings at December 31, 2014. December 31, 2014 Less Than 12 Months 12 Months or Longer Total Temporarily Impaired Investments Fair Value Unrealized Fair Value Unrealized Fair Value Unrealized (In thousands) U.S. Government Sponsored Enterprises $ 22,414 $ 25 $ 14,776 $ 224 $ 37,190 $ 249 U.S. Government Agency and Sponsored Enterprise Mortgage-Backed Securities 194,119 1,678 308,526 5,154 502,645 6,832 Total temporarily impaired securities $ 216,533 $ 1,703 $ 323,302 $ 5,378 $ 539,835 $ 7,081

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	6 Months Ended
	Jun. 30, 2015
Receivables [Abstract]
Summary of Changes in Allowance for Loan Losses	The following table summarizes the changes in the Company’s allowance for loan losses for the periods indicated. Three months ended Six months ended June 30, June 30, 2015 2014 2015 2014 (In thousands) Allowance for loan losses, beginning of period $ 22,529 $ 21,259 $ 22,318 $ 20,941 Loans charged off (403 ) (113 ) (484 ) (542 ) Recoveries on loans previously charged-off 119 126 211 273 Net recoveries (charge-offs) (284 ) 13 (273 ) (269 ) Provision charged to expense — 450 200 1,050 Allowance for loan losses, end of period $ 22,245 $ 21,722 $ 22,245 $ 21,722
Summary of Allowance for Loan Losses	Further information pertaining to the allowance for loan losses for the three months ending June 30, 2015 follows: Construction and Land Commercial and Industrial Municipal Commercial Estate Residential Real Estate Consumer Home Equity Unallocated Total (In thousands) Allowance for loan losses: Balance at March 31, 2015 $ 1,884 $ 4,645 $ 1,373 $ 11,127 $ 799 $ 714 $ 614 $ 1,373 $ 22,529 Charge-offs — (52 ) — (298 ) — (53 ) — — (403 ) Recoveries — 56 — 2 2 59 — — 119 Provision (151 ) (221 ) (373 ) 892 (79 ) (11 ) 36 (93 ) — Ending balance at June 30, 2015 $ 1,733 $ 4,428 $ 1,000 $ 11,723 $ 722 $ 709 $ 650 $ 1,280 $ 22,245 Amount of allowance for loan losses for loans deemed to be impaired $ 12 $ 43 $ — $ 108 $ 41 $ — $ 91 $ — 295 Amount of allowance for loan losses for loans not deemed to be impaired $ 1,721 $ 4,385 $ 1,000 $ 11,615 $ 681 $ 709 $ 559 $ 1,280 $ 21,950 Loans: Ending balance $ 26,521 $ 291,142 $ 87,241 $ 713,770 $ 248,103 $ 10,646 $ 167,271 $ — $ 1,544,694 Loans deemed to be impaired $ 101 $ 595 $ — $ 1,705 $ 941 $ — $ 91 $ — $ 3,433 Loans not deemed to be impaired $ 26,420 $ 290,547 $ 87,241 $ 712,065 $ 247,162 $ 10,646 $ 167,180 $ — $ 1,541,261 Further information pertaining to the allowance for loan losses for the six months ending June 30, 2015 follows: Construction and Land Commercial and Industrial Municipal Commercial Estate Residential Real Estate Consumer Home Equity Unallocated Total (In thousands) Allowance for loan losses: Balance at December 31, 2014 $ 1,592 $ 4,758 $ 1,488 $ 11,199 $ 775 $ 810 $ 599 $ 1,097 $ 22,318 Charge-offs — (52 ) — (298 ) — (134 ) — — (484 ) Recoveries — 71 — 4 4 132 — — 211 Provision 141 (349 ) (488 ) 818 (57 ) (99 ) 51 183 200 Ending balance at June 30, 2015 $ 1,733 $ 4,428 $ 1,000 $ 11,723 $ 722 $ 709 $ 650 $ 1,280 $ 22,245 Amount of allowance for loan losses for loans deemed to be impaired $ 12 $ 43 $ — $ 108 $ 41 $ — $ 91 $ — 295 Amount of allowance for loan losses for loans not deemed to be impaired $ 1,721 $ 4,385 $ 1,000 $ 11,615 $ 681 $ 709 $ 559 $ 1,280 $ 21,950 Loans: Ending balance $ 26,521 $ 291,142 $ 87,241 $ 713,770 $ 248,103 $ 10,646 $ 167,271 $ — $ 1,544,694 Loans deemed to be impaired $ 101 $ 595 $ — $ 1,705 $ 941 $ — $ 91 $ — $ 3,433 Loans not deemed to be impaired $ 26,420 $ 290,547 $ 87,241 $ 712,065 $ 247,162 $ 10,646 $ 167,180 $ — $ 1,541,261 Further information pertaining to the allowance for loan losses for the three months ending June 30, 2014 follows: Construction Commercial Municipal Commercial Residential Consumer Home Unallocated Total (In thousands) Allowance for loan losses: Balance at March 31, 2014 $ 1,825 $ 2,593 $ 804 $ 11,567 $ 1,873 $ 425 $ 902 $ 1,270 $ 21,259 Charge-offs — (14 ) — — — (99 ) — — (113 ) Recoveries — 24 — 2 15 84 1 — 126 Provision 220 (173 ) (41 ) 128 39 18 12 247 450 Ending balance at June 30, 2014 $ 2,045 $ 2,430 $ 763 $ 11,697 $ 1,927 $ 428 $ 915 $ 1,517 $ 21,722 Amount of allowance for loan losses for loans deemed to be impaired $ 273 $ 353 $ — $ 359 $ 160 $ — $ 93 $ — 1. 238 Amount of allowance for loan losses for loans not deemed to be impaired $ 1,772 $ 2,077 $ 763 $ 11,338 $ 1,767 $ 428 $ 822 $ 1,517 $ 20,484 Loans: Ending balance $ 25,861 $ 73,204 $ 31,982 $ 750,445 $ 282,468 $ 9,649 $ 140,616 $ — $ 1,314,225 Loans deemed to be impaired $ 356 $ 1,093 $ — $ 4,775 $ 1,559 $ — $ 93 $ — $ 7,876 Loans not deemed to be impaired $ 25,505 $ 72,111 $ 31,982 $ 745,670 $ 280,909 $ 9,649 $ 140,523 $ — $ 1,306,349 Further information pertaining to the allowance for loan losses for the six months ending June 30, 2014 follows: Construction Commercial Municipal Commercial Residential Consumer Home Unallocated Total (In thousands) Allowance for loan losses: Balance at December 31, 2013 $ 2,174 $ 2,617 $ 655 $ 10,935 $ 2,006 $ 432 $ 959 $ 1,163 $ 20,941 Charge-offs (250 ) (14 ) — — — (278 ) — — (542 ) Recoveries — 48 — 4 20 200 1 — 273 Provision 121 (221 ) 108 758 (99 ) 74 (45 ) 354 1,050 Ending balance at June 30, 2014 $ 2,045 $ 2,430 $ 763 $ 11,697 $ 1,927 $ 428 $ 915 $ 1,517 $ 21,722 Amount of allowance for loan losses for loans deemed to be impaired $ 273 $ 353 $ — $ 359 $ 160 $ — $ 93 $ — 1. 238 Amount of allowance for loan losses for loans not deemed to be impaired $ 1,772 $ 2,077 $ 763 $ 11,338 $ 1,767 $ 428 $ 822 $ 1,517 $ 20,484 Loans: Ending balance $ 25,861 $ 73,204 $ 31,982 $ 750,445 $ 282,468 $ 9,649 $ 140,616 $ — $ 1,314,225 Loans deemed to be impaired $ 356 $ 1,093 $ — $ 4,775 $ 1,559 $ — $ 93 $ — $ 7,876 Loans not deemed to be impaired $ 25,505 $ 72,111 $ 31,982 $ 745,670 $ 280,909 $ 9,649 $ 140,523 $ — $ 1,306,349
Loans by Risk Rating	The following table presents the Company’s loans by risk rating at June 30, 2015. Construction and Land Development Commercial and Industrial Municipal Commercial Estate (In thousands) Grade: 1-3 (Pass) $ 19,396 $ 290,547 $ 87,241 $ 711,449 4 (Monitor) 7,024 — — 616 5 (Substandard) — — — — 6 (Doubtful) — — — — Impaired 101 595 — 1,705 Total $ 26,521 $ 291,142 $ 87,241 $ 713,770 The following table presents the Company’s loans by risk rating at December 31, 2014. Construction Commercial Municipal Commercial (In thousands) Grade: 1-3 (Pass) $ 15,515 $ 148,407 $ 41,850 $ 691,322 4 (Monitor) 7,126 472 — 633 5 (Substandard) — — — — 6 (Doubtful) — — — — Impaired 103 853 — 4,317 Total $ 22,744 $ 149,732 $ 41,850 $ 696,272
Loans by Credit Ratings Issued by National Organizations	As of June 30, 2015, the Company incorporated this information into the development of the historical loss rates for these loan types. Credit ratings issued by national organizations were utilized as credit quality indicators as presented in the following table at June 30, 2015. Commercial and Industrial Municipal Commercial Estate (In thousands) Credit Rating: Aaa – Aa3 $ 135,059 $ 60,483 $ 8,014 A1 – A3 80,385 7,820 131,641 Baa1 – Baa3 — 9,035 154,699 Ba2 — 4,480 — Total $ 215,444 $ 81,818 $ 294,354
Aging of Past Due Loan Losses	Further information pertaining to the allowance for loan losses at June 30, 2015 follows: Accruing 30-89 Days Past Due Non Accrual Accruing Greater Than 90 Days Total Past Due Current Loans Total (In thousands) Construction and land development $ — $ 101 $ — $ 101 $ 26,420 $ 26,521 Commercial and industrial — 122 — 122 291,020 291,142 Municipal — — — — 87,241 87,241 Commercial real estate 926 186 — 1,112 712,658 713,770 Residential real estate 927 1,136 — 2,063 246,040 248,103 Consumer and overdrafts 8 3 — 11 10,635 10,646 Home equity 407 638 — 1,045 166,226 167,271 Total $ 2,268 $ 2,186 $ — $ 4,454 $ 1,540,240 $ 1,544,694 Further information pertaining to the allowance for loan losses at December 31, 2014 follows: Accruing Non Accrual Accruing Total Current Loans Total (In thousands) Construction and land development $ — $ 103 $ — $ 103 $ 22,641 $ 22,744 Commercial and industrial 905 157 — 1,062 148,670 149,732 Municipal — — — — 41,850 41,850 Commercial real estate 1,046 2,781 — 3,827 692,445 696,272 Residential real estate 632 846 — 1,478 255,827 257,305 Consumer and overdrafts 6 5 — 11 12,177 12,188 Home equity 576 254 — 830 150,445 151,275 Total $ 3,165 $ 4,146 $ — $ 7,311 $ 1,324,055 $ 1,331,366
Information Pertaining to Impaired Loans	The following is information pertaining to impaired loans for June 30, 2015: Carrying Value Unpaid Principal Balance Required Reserve Average Ending 6/30/15 Interest Income Recognized For 3 Months Average Ending 6/30/15 Interest Income Recognized For 6 Months (Dollars in thousands) With no required reserve recorded: Construction and land development $ — $ — $ — $ — $ — $ — $ — Commercial and industrial 32 32 — 47 — 40 — Municipal — — — — — — — Commercial real estate — — — 196 — 280 — Residential real estate 126 210 — 129 2 131 4 Consumer — — — — — — — Home equity — — — — — — — Total $ 158 $ 242 $ — $ 372 $ 2 $ 451 $ 4 With required reserve recorded: Construction and land development $ 101 $ 108 $ 12 $ 102 $ — $ 102 $ — Commercial and industrial 563 765 43 644 5 722 11 Municipal — — — — — — — Commercial real estate 1,705 1,801 108 2,809 17 3,286 33 Residential real estate 815 815 41 817 1 820 7 Consumer — — — — — — — Home equity 91 91 91 91 — 92 — Total $ 3,275 $ 3,580 $ 295 $ 4,463 $ 23 $ 5,022 $ 51 Total: Construction and land development $ 101 $ 108 $ 12 $ 102 $ — $ 102 $ — Commercial and industrial 595 797 43 691 5 762 11 Municipal — — — — — — — Commercial real estate 1,705 1,801 108 3,005 17 3,566 33 Residential real estate 941 1,025 41 946 3 951 11 Consumer — — — — — — — Home equity 91 91 91 91 — 92 — Total $ 3,433 $ 3,822 $ 295 $ 4,835 $ 25 $ 5,473 $ 55 The following is information pertaining to impaired loans for June 30, 2014: Carrying Value Unpaid Required Average Interest Average Interest (Dollars in thousands) With no required reserve recorded: Construction and land development $ — $ — $ — $ 188 $ — $ 321 $ — Commercial and industrial 11 42 — 11 — 71 — Commercial real estate 400 400 — 100 — 80 — Residential real estate 70 70 — 31 — 104 — Consumer — — — — — — — Home equity — — — — — — — Total $ 481 $ 512 $ — $ 330 $ — $ 576 $ — With required reserve recorded: Construction and land development $ 356 $ 3,400 $ 273 $ 169 $ — $ 143 $ — Commercial and industrial 1,082 1,332 353 1,095 8 1,104 19 Commercial real estate 4,375 4,466 359 4,391 36 4,405 74 Residential real estate 1,489 1,684 160 1,106 3 1,039 5 Consumer — — — — — — — Home equity 93 93 93 94 — 94 — Total $ 7,395 $ 10,975 $ 1,238 $ 6,855 $ 47 $ 6,785 $ 98 Total: Construction and land development $ 356 $ 3,400 $ 273 $ 357 $ — $ 465 $ — Commercial and industrial 1,093 1,374 353 1,106 8 1,175 19 Commercial real estate 4,775 4,866 359 4,491 36 4,485 74 Residential real estate 1,559 1,754 160 1,137 3 1,143 5 Consumer — — — — — — — Home equity 93 93 93 94 — 94 — Total $ 7,876 $ 11,487 $ 1,238 $ 7,185 $ 47 $ 7,362 $ 98

Reclassifications Out of Accu22

Reclassifications Out of Accumulated Other Comprehensive Income (Tables)	6 Months Ended
	Jun. 30, 2015
Text Block [Abstract]
Reclassifications Out of Accumulated Other Comprehensive Income	Amount Reclassified from Accumulated Other Comprehensive Income Details about Accumulated Other Comprehensive Income Components Three Months Ended June 30, 2015 Three Months Ended June 30, 2014 Affected Line Item in the Statement Where Net Income is Presented (in thousands) Unrealized gains and losses on available-for-sale securities $ 118 $ — Net gains on sales of securities (47 ) — Provision for income taxes $ 71 $ — Net income Accretion of unrealized losses transferred $ 1,576 $ 1,286 Interest on securities held-to-maturity (549 ) (478 ) Provision for income taxes $ 1,027 $ 808 Net income Amortization of defined benefit pension items Prior-service costs $ (3 )(b) $ (3 )(b) Salaries and employee benefits Actuarial gains (losses) (352 )(b) (91 )(b) Salaries and employee benefits Total before tax (355 ) (94 ) Income before taxes Tax (expense) or benefit 142 38 Provision for income taxes Net of tax $ (213 ) $ (56 ) Net income Total reclassifications for the period $ 885 $ 752 Net income, net of tax Details about Accumulated Other Comprehensive Income Components Six Months Ended Six Months Ended Affected Line Item in the Statement Where Net Income is Presented (in thousands) Unrealized gains and losses on available-for-sale securities $ 118 $ — Net gains on sales of securities (47 ) — Provision for income taxes $ 71 $ — Net income Accretion of unrealized losses transferred $ 2,705 $ 2,793 Interest on securities held-to-maturity (943 ) (1,061 ) Provision for income taxes $ 1,762 $ 1,732 Net income Amortization of defined benefit pension items Prior-service costs $ (6 )(b) $ (5 )(b) Salaries and employee benefits Actuarial gains (losses) (704 )(b) (183 )(b) Salaries and employee benefits Total before tax (710 ) (188 ) Income before taxes Tax (expense) or benefit 284 75 Provision for income taxes Net of tax $ (426 ) $ (113 ) Net income Total reclassifications for the period $ 1,407 $ 1,619 Net income, net of tax (a) Amount in parentheses indicate debits to profit/loss. (b) These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see employee benefits footnote (Note 8) for additional details).

Earnings per Share ("EPS") (Tab

Earnings per Share ("EPS") (Tables)	6 Months Ended
	Jun. 30, 2015
Earnings Per Share [Abstract]
Reconciliation of Basic EPS and Diluted EPS	The following table is a reconciliation of basic EPS and diluted EPS for the three and six months ended June 30, Three Months Ended June 30, Six Months Ended June 30, 2015 2014 2015 2014 Basic EPS Computation: Numerator: Net income, Class A $ 4,654 $ 4,394 $ 8,549 $ 8,259 Net income, Class B 1,271 1,205 2,335 2,272 Denominator: Weighted average shares outstanding, Class A 3,600,729 3,589,125 3,600,729 3,585,773 Weighted average shares outstanding, Class B 1,967,180 1,967,580 1,967,180 1,970,880 Basic EPS, Class A $ 1.29 $ 1.22 $ 2.37 $ 2.30 Basic EPS, Class B 0.65 0.61 1.19 1.15 Diluted EPS Computation: Numerator: Net income, Class A $ 4,654 $ 4,394 $ 8,549 $ 8,259 Net income, Class B 1,271 1,205 2,335 2,272 Total net income, for diluted EPS, Class A computation 5,925 5,599 10,884 10,531 Denominator: Weighted average shares outstanding, basic, Class A 3,600,729 3,589,125 3,600,729 3,585,773 Weighted average shares outstanding, Class B 1,967,180 1,967,580 1,967,180 1,970,880 Dilutive effect of Class A stock options — 1,327 — 1,452 Weighted average shares outstanding diluted, Class A 5,567,909 5,558,032 5,567,909 5,558,105 Weighted average shares outstanding, Class B 1,967,180 1,967,580 1,967,180 1,970,880 Diluted EPS, Class A $ 1.06 $ 1.01 $ 1.95 $ 1.89 Diluted EPS, Class B 0.65 0.61 1.19 1.15

Employee Benefits (Tables)

Employee Benefits (Tables)	6 Months Ended
	Jun. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Components of Net Periodic Benefit Cost (Credit)	Components of Net Periodic Benefit Cost (Credit) for the Three Months Ended June 30, Pension Benefits Supplemental Insurance/ Retirement Plan 2015 2014 2015 2014 (In thousands) Service cost $ 336 $ 258 $ 397 $ 389 Interest 394 367 341 331 Expected return on plan assets (688 ) (636 ) — — Recognized prior service cost (benefit) (26 ) (26 ) 29 29 Recognized net actuarial losses 204 3 149 88 Net periodic benefit (credit) cost $ 220 $ (34 ) $ 916 $ 837 Components of Net Periodic Benefit Cost (Credit) for the Six Months Ended June 30, Pension Benefits Supplemental Insurance/ Retirement Plan 2015 2014 2015 2014 (In thousands) Service cost $ 672 $ 516 $ 794 $ 778 Interest 788 734 682 662 Expected return on plan assets (1,376 ) (1,272 ) — — Recognized prior service cost (benefit) (52 ) (52 ) 58 58 Recognized net actuarial losses 407 6 299 176 Net periodic benefit (credit) cost $ 439 $ (68 ) $ 1,833 $ 1,674

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2015
Fair Value Disclosures [Abstract]
Financial Instruments Measured at Fair Value on a Recurring and Non-recurring Basis	The results of the fair value hierarchy as of June 30, 2015, are as follows: Financial Instruments Measured at Fair Value on a Recurring Basis: Securities AFS Fair Value Measurements Using Carrying Quoted Prices In Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) (In thousands) U.S. Treasury $ 1,997 $ — $ 1,997 $ — SBA Backed Securities 6,494 — 6,494 — U.S. Government Agency and Sponsored Mortgage Backed Securities 273,563 — 273,563 — Privately Issued Residential Mortgage Backed Securities 1,641 — 1,641 — Obligations Issued by States and Political Subdivisions 152,541 — — 152,541 Other Debt Securities 3,499 — 3,499 — Equity Securities 324 287 — 37 Total $ 440,059 $ 287 $ 287,194 $ 152,578 Financial Instruments Measured at Fair Value on a Non-recurring Basis: Impaired Loans 1,159 — — 1,159 Other Real Estate Owned 1,916 1,916 The results of the fair value hierarchy as of December 31, 2014, are as follows: Financial Instruments Measured at Fair Value on a Recurring Basis: Securities AFS Fair Value Measurements Using Carrying Quoted Prices In Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Other Unobservable Inputs (Level 3) (In thousands) U.S. Treasury $ 2,000 $ — $ 2,000 $ — U.S. Government Sponsored Enterprises — — — — SBA Backed Securities 6,717 — 6,717 — U.S. Government Agency and Sponsored Mortgage Backed Securities 337,093 — 337,093 — Privately Issued Residential Mortgage Backed Securities 1,874 — 1,874 — Obligations Issued by States and Political Subdivisions 96,784 — — 96,784 Other Debt Securities 3,524 — 3,524 — Equity Securities 398 296 — 102 Total $ 448,390 $ 296 $ 351,208 $ 96,886 Financial Instruments Measured at Fair Value on a Non-recurring Basis: Impaired Loans 3,410 — — 3,410
Assets Measured at Fair Value	The following table presents additional information about assets measured at fair value on a recurring and nonrecurring basis for which the Company has utilized Level 3 inputs to determine fair value (dollars in thousands). Management continues to monitor the assumptions used to value the assets listed below. Asset Fair Value Valuation Technique Unobservable Input Unobservable Input Value or Range Securities AFS (4) $ 152,578 Discounted cash flow Discount rate 0%-1% (3) Impaired Loans 1,159 Appraisal of collateral (1) Appraisal adjustments (2) 0%-30% discount Other Real Estate Owned 1,916 Appraisal (1) Appraisal adjustments (2) 0%-30% discount (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various Level 3 inputs which are not identifiable. (2) Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated expenses. (3) Weighted averages. (4) Municipal securities generally have maturities of one year or less and, therefore, the amortized cost equates to the fair value. The following table presents additional information about assets measured at fair value on a recurring and nonrecurring basis for which the Company has utilized Level 3 inputs to determine fair value (dollars in thousands). Management continues to monitor the assumptions used to value the assets listed below. Asset Fair Valuation Technique Unobservable Input Unobservable Input Value or Range Securities AFS (4) $ 96,886 Discounted cash flow Discount rate 0%-1% (3) Impaired Loans 3,410 Appraisal of collateral (1) Appraisal adjustments (2) 0%-30% discount (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various Level 3 inputs which are not identifiable. (2) Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated expenses. (3) Weighted averages (4) Municipal securities generally have maturities of one year or less and, therefore, the amortized cost equates to the fair value.
Changes in Level 3 Securities	The changes in Level 3 securities for the six-month period ended June 30, 2015 are shown in the table below: Auction Securities Obligations Equity Total (In thousands) Balance at December 31, 2014 $ 3,820 $ 92,964 $ 102 $ 96,886 Purchases — 113,179 — 113,179 Maturities and calls — (57,411 ) (65 ) (57,476 ) Amortization — (11 ) — (11 ) Changes in fair value — — — — Balance at June 30, 2015 $ 3,820 $ 148,721 $ 37 $ 152,578 The changes in Level 3 securities for the six-month period ended June 30, 2014, are shown in the table below: Auction Securities Obligations Equity Total (In thousands) Balance at December 31, 2013 $ 3,820 $ 32,487 $ 290 $ 36,597 Purchases — 51,471 — 51,471 Maturities and calls — (27,282 ) (79 ) (27,361 ) Amortization — (2 ) — (2 ) Changes in fair value — — — — Balance at June 30, 2014 $ 3,820 $ 56,674 $ 211 $ 60,705

Fair Values of Financial Inst26

Fair Values of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2015
Investments, All Other Investments [Abstract]
Carrying Amounts and Fair Values of Company's Financial Instruments	The following presents (in thousands) the carrying amount, estimated fair value, and placement in the fair value hierarchy of the Company’s financial instruments as of June 30, 2015 and December 31, 2014. This table excludes financial instruments for which the carrying amount approximates fair value. Financial assets for which the fair value approximates carrying value include cash and cash equivalents, short-term investments, FHLBB stock and accrued interest receivable. Financial liabilities for which the fair value approximates carrying value include non-maturity deposits, short-term borrowings and accrued interest payable. Fair Value Measurements Carrying Estimated Level 1 Level 2 Level 3 (In thousands) June 30, 2015 Financial assets: Securities held-to-maturity $ 1,683,568 $ 1,689,572 $ — $ 1,689,572 $ — Loans (1) 1,522,449 1,503,326 — — 1,503,326 Financial liabilities: Time deposits 383,284 387,675 — 387,675 — Other borrowed funds 485,500 487,271 — 487,271 — Subordinated debentures 36,083 36,083 — — 36,083 December 31, 2014 Financial assets: Securities held-to-maturity 1,406,792 1,413,603 — 1,413,603 — Loans (1) 1,309,048 1,291,550 — — 1,291,550 Financial liabilities: Time deposits 383,145 387,919 — 387,919 — Other borrowed funds 395,500 400,196 — 400,196 — Subordinated debentures 36,083 36,083 — — 36,083 (1) Comprised of loans (including collateral dependent impaired loans), net of deferred loan costs and the allowance for loan losses.

Basis of Financial Statement 27

Basis of Financial Statement Presentation - Additional Information (Detail) - Jun. 30, 2015 - Segment	Total
Basis Of Presentation [Line Items]
Number of reportable segments	1
Century Bancorp Capital Trust II [Member]
Basis Of Presentation [Line Items]
Equity ownership interest	100.00%

Securities Available-for-Sale -

Securities Available-for-Sale - Summary of Securities Available-for-Sale (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 440,044	$ 448,210
Gross Unrealized Gains	1,351	1,630
Gross Unrealized Losses	1,336	1,450
Total, Fair Value	440,059	448,390
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,999	1,999
Gross Unrealized Gains		1
Gross Unrealized Losses	2
Total, Fair Value	1,997	2,000
Small Business Administration [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,446	6,684
Gross Unrealized Gains	48	33
Total, Fair Value	6,494	6,717
U.S. Government Agency and Sponsored Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	272,775	336,158
Gross Unrealized Gains	1,114	1,387
Gross Unrealized Losses	326	452
Total, Fair Value	273,563	337,093
Privately Issued Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,654	1,894
Gross Unrealized Gains	4	5
Gross Unrealized Losses	17	25
Total, Fair Value	1,641	1,874
Obligations Issued by States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	153,417	97,657
Gross Unrealized Losses	876	873
Total, Fair Value	152,541	96,784
Other Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	3,600	3,600
Gross Unrealized Gains	14	24
Gross Unrealized Losses	115	100
Total, Fair Value	3,499	3,524
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	153	218
Gross Unrealized Gains	171	180
Total, Fair Value	$ 324	$ 398

Securities Available-for-Sale29

Securities Available-for-Sale - Additional Information (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2015USD ($)Security	Sep. 30, 2013USD ($)	Jun. 30, 2015USD ($)Security	Dec. 31, 2014USD ($)Security
Schedule of Available-for-sale Securities [Line Items]
Securities available-for-sale with an amortized cost		$ 1,012,370,000
Securities held-to-maturity at their fair value		$ 987,037,000
Net gains on sales of securities	$ 118,000		$ 118,000
Proceeds from sales of securities available-for-sale			$ 21,215,000
Weighted average remaining life of investment securities available-for-sale			3 years 8 months 12 days
Federal Home Loan Bank of Boston [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available-for-sale are securities pledged for borrowing	22,268,000		$ 22,268,000	$ 24,810,000
Net gains on sales of securities			118,000
U.S. Government Agency and Sponsored Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities at fair value pledged to secure public deposits and repurchase agreements	$ 256,228,000		$ 256,228,000	$ 301,038,000
Securities AFS [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities, temporarily impaired for less than 12 months | Security	5		5	3
Number of securities, temporarily impaired for 12 months or longer | Security	14		14	14
Number of securities, temporarily impaired, total | Security	285		285	262

Securities Available-for-Sale30

Securities Available-for-Sale - Maturity Distribution of Securities Available-for-Sale (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Within one year, Amortized Cost	$ 147,326
After one but within five years, Amortized Cost	161,584
After five but within ten years, Amortized Cost	121,460
More than 10 years, Amortized Cost	8,021
Non-maturing, Amortized Cost	1,653
Amortized Cost	440,044	$ 448,210
Within one year, Fair Value	147,327
After one but within five years, Fair Value	162,236
After five but within ten years, Fair Value	121,600
More than 10 years, Fair Value	7,187
Non-maturing, Fair Value	1,709
Total, Fair Value	$ 440,059	$ 448,390

Securities Available-for-Sale31

Securities Available-for-Sale - Continuous Unrealized Loss Position for 12 Months or Less and 12 Months or Longer (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	$ 9,731	$ 24,457
Less than 12 months, Unrealized Losses	8	85
12 months or longer, Fair Value	80,166	83,483
12 months or longer, Unrealized Losses	1,328	1,365
Total, Fair Value	89,897	107,940
Total, Unrealized Losses	1,336	1,450
U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	1,997
Less than 12 months, Unrealized Losses	2
Total, Fair Value	1,997
Total, Unrealized Losses	2
U.S. Government Agency and Sponsored Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	7,335	24,457
Less than 12 months, Unrealized Losses	5	85
12 months or longer, Fair Value	74,363	77,585
12 months or longer, Unrealized Losses	321	367
Total, Fair Value	81,698	102,042
Total, Unrealized Losses	326	452
Privately Issued Residential Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
12 months or longer, Fair Value	597	678
12 months or longer, Unrealized Losses	17	25
Total, Fair Value	597	678
Total, Unrealized Losses	17	25
Obligations Issued by States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
12 months or longer, Fair Value	3,820	3,820
12 months or longer, Unrealized Losses	876	873
Total, Fair Value	3,820	3,820
Total, Unrealized Losses	876	873
Other Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 months, Fair Value	399
Less than 12 months, Unrealized Losses	1
12 months or longer, Fair Value	1,386	1,400
12 months or longer, Unrealized Losses	114	100
Total, Fair Value	1,785	1,400
Total, Unrealized Losses	$ 115	$ 100

Investment Securities Held-to32

Investment Securities Held-to-Maturity - Summary of Held-to-Maturity Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 1,683,568	$ 1,406,792
Gross Unrealized Gains	13,940	13,892
Gross Unrealized Losses	7,936	7,081
Estimated Fair Value	1,689,572	1,413,603
U.S. Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	319,405	251,617
Gross Unrealized Gains	3,233	2,707
Gross Unrealized Losses	392	249
Estimated Fair Value	322,246	254,075
U.S. Government Agency and Sponsored Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,364,163	1,155,175
Gross Unrealized Gains	10,707	11,185
Gross Unrealized Losses	7,544	6,832
Estimated Fair Value	$ 1,367,326	$ 1,159,528

Investment Securities Held-to33

Investment Securities Held-to-Maturity - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2015USD ($)Security	Dec. 31, 2014USD ($)Security
Schedule of Held-to-maturity Securities [Line Items]
Weighted average remaining life of investment securities held-to-maturity	4 years 6 months
Held-to-Maturity Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Number of securities, temporarily impaired for less than 12 months	98	34
Number of securities, temporarily impaired for 12 months or longer	22	48
Number of securities, temporarily impaired, total	352	303
Federal Home Loan Bank of Boston [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities pledged for borrowing at the Federal Home Loan Bank of Boston | $	$ 411,957,000	$ 458,782,000
U.S. Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Securities at fair value pledged to secure public deposits and repurchase agreements | $	1,062,575,000	$ 868,924,000
Weighted average remaining life | $	$ 202,373,000

Investment Securities Held-to34

Investment Securities Held-to-Maturity - Company's Securities Held-to-Maturity (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Within one year, Amortized Cost	$ 2,854
After one but within five years, Amortized Cost	1,264,143
After five but within ten years, Amortized Cost	406,814
More than ten years, Amortized Cost	9,757
Amortized Cost	1,683,568	$ 1,406,792
Within one year, Fair Value	2,895
After one but within five years, Fair Value	1,268,516
After five but within ten years, Fair Value	408,543
More than ten years, Fair Value	9,618
Estimated Fair Value	$ 1,689,572	$ 1,413,603

Investment Securities Held-to35

Investment Securities Held-to-Maturity - Unrealized Market Loss of Securities (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Schedule of Held-to-maturity Securities [Line Items]
Less Than 12 Months, Fair Value	$ 652,968	$ 216,533
Less Than 12 Months, Unrealized Losses	5,327	1,703
12 Months or Longer, Fair Value	123,344	323,302
12 Months or Longer, Unrealized Losses	2,609	5,378
Total, Fair Value	776,312	539,835
Total, Unrealized Losses	7,936	7,081
U.S. Government Sponsored Enterprises [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less Than 12 Months, Fair Value	91,968	22,414
Less Than 12 Months, Unrealized Losses	392	25
12 Months or Longer, Fair Value		14,776
12 Months or Longer, Unrealized Losses		224
Total, Fair Value	91,968	37,190
Total, Unrealized Losses	392	249
U.S. Government Agency and Sponsored Mortgage Backed Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Less Than 12 Months, Fair Value	561,000	194,119
Less Than 12 Months, Unrealized Losses	4,935	1,678
12 Months or Longer, Fair Value	123,344	308,526
12 Months or Longer, Unrealized Losses	2,609	5,154
Total, Fair Value	684,344	502,645
Total, Unrealized Losses	$ 7,544	$ 6,832

Allowance for Loan Losses - Sum

Allowance for Loan Losses - Summary of Changes in Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Receivables [Abstract]
Allowance for loan losses, beginning of period	$ 22,529	$ 21,259	$ 22,318	$ 20,941
Loans charged off	(403)	(113)	(484)	(542)
Recoveries on loans previously charged-off	119	126	211	273
Net recoveries (charge-offs)	(284)	13	(273)	(269)
Provision charged to expense		450	200	1,050
Allowance for loan losses, end of period	$ 22,245	$ 21,722	$ 22,245	$ 21,722

Allowance for Loan Losses - S37

Allowance for Loan Losses - Summary of Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Allowance for loan losses:
Allowance for loan losses, beginning of period	$ 22,529	$ 21,259	$ 22,318	$ 20,941
Charge-offs	(403)	(113)	(484)	(542)
Recoveries	119	126	211	273
Provision		450	200	1,050
Allowance for loan losses, end of period	22,245	21,722	22,245	21,722
Amount of allowance for loan losses for loans deemed to be impaired	295	1,238	295	1,238
Amount of allowance for loan losses for loans not deemed to be impaired	21,950	20,484	21,950	20,484
Loans:
Total loans, net	1,544,694	1,314,225	1,544,694	1,314,225	$ 1,331,366
Loans deemed to be impaired	3,433	7,876	3,433	7,876
Loans not deemed to be impaired	1,541,261	1,306,349	1,541,261	1,306,349
Construction and Land Development [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	1,884	1,825	1,592	2,174
Charge-offs				(250)
Provision	(151)	220	141	121
Allowance for loan losses, end of period	1,733	2,045	1,733	2,045
Amount of allowance for loan losses for loans deemed to be impaired	12	273	12	273
Amount of allowance for loan losses for loans not deemed to be impaired	1,721	1,772	1,721	1,772
Loans:
Total loans, net	26,521	25,861	26,521	25,861	22,744
Loans deemed to be impaired	101	356	101	356
Loans not deemed to be impaired	26,420	25,505	26,420	25,505
Commercial and Industrial [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	4,645	2,593	4,758	2,617
Charge-offs	(52)	(14)	(52)	(14)
Recoveries	56	24	71	48
Provision	(221)	(173)	(349)	(221)
Allowance for loan losses, end of period	4,428	2,430	4,428	2,430
Amount of allowance for loan losses for loans deemed to be impaired	43	353	43	353
Amount of allowance for loan losses for loans not deemed to be impaired	4,385	2,077	4,385	2,077
Loans:
Total loans, net	291,142	73,204	291,142	73,204	149,732
Loans deemed to be impaired	595	1,093	595	1,093
Loans not deemed to be impaired	290,547	72,111	290,547	72,111
Municipal [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	1,373	804	1,488	655
Provision	(373)	(41)	(488)	108
Allowance for loan losses, end of period	1,000	763	1,000	763
Amount of allowance for loan losses for loans not deemed to be impaired	1,000	763	1,000	763
Loans:
Total loans, net	87,241	31,982	87,241	31,982	41,850
Loans not deemed to be impaired	87,241	31,982	87,241	31,982
Commercial Real Estate [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	11,127	11,567	11,199	10,935
Charge-offs	(298)		(298)
Recoveries	2	2	4	4
Provision	892	128	818	758
Allowance for loan losses, end of period	11,723	11,697	11,723	11,697
Amount of allowance for loan losses for loans deemed to be impaired	108	359	108	359
Amount of allowance for loan losses for loans not deemed to be impaired	11,615	11,338	11,615	11,338
Loans:
Total loans, net	713,770	750,445	713,770	750,445	696,272
Loans deemed to be impaired	1,705	4,775	1,705	4,775
Loans not deemed to be impaired	712,065	745,670	712,065	745,670
Residential Real Estate [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	799	1,873	775	2,006
Recoveries	2	15	4	20
Provision	(79)	39	(57)	(99)
Allowance for loan losses, end of period	722	1,927	722	1,927
Amount of allowance for loan losses for loans deemed to be impaired	41	160	41	160
Amount of allowance for loan losses for loans not deemed to be impaired	681	1,767	681	1,767
Loans:
Total loans, net	248,103	282,468	248,103	282,468	257,305
Loans deemed to be impaired	941	1,559	941	1,559
Loans not deemed to be impaired	247,162	280,909	247,162	280,909
Consumer [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	714	425	810	432
Charge-offs	(53)	(99)	(134)	(278)
Recoveries	59	84	132	200
Provision	(11)	18	(99)	74
Allowance for loan losses, end of period	709	428	709	428
Amount of allowance for loan losses for loans not deemed to be impaired	709	428	709	428
Loans:
Total loans, net	10,646	9,649	10,646	9,649	12,188
Loans not deemed to be impaired	10,646	9,649	10,646	9,649
Home Equity [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	614	902	599	959
Recoveries		1		1
Provision	36	12	51	(45)
Allowance for loan losses, end of period	650	915	650	915
Amount of allowance for loan losses for loans deemed to be impaired	91	93	91	93
Amount of allowance for loan losses for loans not deemed to be impaired	559	822	559	822
Loans:
Total loans, net	167,271	140,616	167,271	140,616	$ 151,275
Loans deemed to be impaired	91	93	91	93
Loans not deemed to be impaired	167,180	140,523	167,180	140,523
Unallocated [Member]
Allowance for loan losses:
Allowance for loan losses, beginning of period	1,373	1,270	1,097	1,163
Provision	(93)	247	183	354
Allowance for loan losses, end of period	1,280	1,517	1,280	1,517
Amount of allowance for loan losses for loans not deemed to be impaired	$ 1,280	$ 1,517	$ 1,280	$ 1,517

Allowance for Loan Losses - Loa

Allowance for Loan Losses - Loans by Risk Rating (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Loans by risk rating
Financing Receivable, Net	$ 1,544,694	$ 1,331,366	$ 1,314,225
Construction and Land Development [Member]
Loans by risk rating
Financing Receivable, Net	26,521	22,744	25,861
Construction and Land Development [Member] | 1-3 (Pass) [Member]
Loans by risk rating
Financing Receivable, Net	19,396	15,515
Construction and Land Development [Member] | 4 (Monitor) [Member]
Loans by risk rating
Financing Receivable, Net	7,024	7,126
Construction and Land Development [Member] | Impaired [Member]
Loans by risk rating
Financing Receivable, Net	101	103
Commercial and Industrial [Member]
Loans by risk rating
Financing Receivable, Net	291,142	149,732	73,204
Commercial and Industrial [Member] | 1-3 (Pass) [Member]
Loans by risk rating
Financing Receivable, Net	290,547	148,407
Commercial and Industrial [Member] | 4 (Monitor) [Member]
Loans by risk rating
Financing Receivable, Net		472
Commercial and Industrial [Member] | Impaired [Member]
Loans by risk rating
Financing Receivable, Net	595	853
Municipal [Member]
Loans by risk rating
Financing Receivable, Net	87,241	41,850	31,982
Municipal [Member] | 1-3 (Pass) [Member]
Loans by risk rating
Financing Receivable, Net	87,241	41,850
Commercial Real Estate [Member]
Loans by risk rating
Financing Receivable, Net	713,770	696,272	$ 750,445
Commercial Real Estate [Member] | 1-3 (Pass) [Member]
Loans by risk rating
Financing Receivable, Net	711,449	691,322
Commercial Real Estate [Member] | 4 (Monitor) [Member]
Loans by risk rating
Financing Receivable, Net	616	633
Commercial Real Estate [Member] | Impaired [Member]
Loans by risk rating
Financing Receivable, Net	$ 1,705	$ 4,317

Allowance for Loan Losses - L39

Allowance for Loan Losses - Loans by Credit Ratings Issued by National Organizations (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	$ 1,544,694	$ 1,331,366	$ 1,314,225
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	215,444
Commercial and Industrial [Member] | Aaa - Aa3 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	135,059
Commercial and Industrial [Member] | A1 - A3 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	80,385
Municipal [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	81,818
Municipal [Member] | Aaa - Aa3 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	60,483
Municipal [Member] | A1 - A3 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	7,820
Municipal [Member] | Baa1 - Baa3 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	9,035
Municipal [Member] | Ba2 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	4,480
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	294,354
Commercial Real Estate [Member] | Aaa - Aa3 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	8,014
Commercial Real Estate [Member] | A1 - A3 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	131,641
Commercial Real Estate [Member] | Baa1 - Baa3 [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivable net of deferred income	$ 154,699

Allowance for Loan Losses - Agi

Allowance for Loan Losses - Aging of Past Due Loan Losses (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Accruing 30-89 Days Past Due	$ 2,268	$ 3,165
Non Accrual	2,186	4,146
Total Past Due	4,454	7,311
Current Loans	1,540,240	1,324,055
Total loans, net	1,544,694	1,331,366	$ 1,314,225
Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Non Accrual	101	103
Total Past Due	101	103
Current Loans	26,420	22,641
Total loans, net	26,521	22,744	25,861
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Accruing 30-89 Days Past Due		905
Non Accrual	122	157
Total Past Due	122	1,062
Current Loans	291,020	148,670
Total loans, net	291,142	149,732	73,204
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Current Loans	87,241	41,850
Total loans, net	87,241	41,850	31,982
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Accruing 30-89 Days Past Due	926	1,046
Non Accrual	186	2,781
Total Past Due	1,112	3,827
Current Loans	712,658	692,445
Total loans, net	713,770	696,272	750,445
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Accruing 30-89 Days Past Due	927	632
Non Accrual	1,136	846
Total Past Due	2,063	1,478
Current Loans	246,040	255,827
Total loans, net	248,103	257,305	282,468
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Accruing 30-89 Days Past Due	8	6
Non Accrual	3	5
Total Past Due	11	11
Current Loans	10,635	12,177
Total loans, net	10,646	12,188	9,649
Home Equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Accruing 30-89 Days Past Due	407	576
Non Accrual	638	254
Total Past Due	1,045	830
Current Loans	166,226	150,445
Total loans, net	$ 167,271	$ 151,275	$ 140,616

Allowance for Loan Losses - Inf

Allowance for Loan Losses - Information Pertaining to Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
With no required reserve recorded, Carrying Value	$ 158	$ 481	$ 158	$ 481
With no required reserve recorded, Unpaid Principal Balance	242	512	242	512
With no required reserve recorded, Required Reserve	0	0	0	0
With no required reserve recorded, Average Carrying Value	372	330	451	576
With no required reserve recorded, Interest Income Recognized	2		4
With required reserve recorded, Carrying Value	3,275	7,395	3,275	7,395
With required reserve recorded, Unpaid Principal Balance	3,580	10,975	3,580	10,975
With required reserve recorded, Required Reserve	295	1,238	295	1,238
With required reserve recorded, Average Carrying Value	4,463	6,855	5,022	6,785
With required reserve recorded, Interest Income Recognized	23	47	51	98
Carrying Value	3,433	7,876	3,433	7,876
Unpaid Principal Balance	3,822	11,487	3,822	11,487
With required reserve recorded, Required Reserve	295	1,238	295	1,238
Average Carrying Value	4,835	7,185	5,473	7,362
Interest Income Recognized	25	47	55	98
Construction and Land Development [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
With no required reserve recorded, Required Reserve	0	0	0	0
With no required reserve recorded, Average Carrying Value		188		321
With required reserve recorded, Carrying Value	101	356	101	356
With required reserve recorded, Unpaid Principal Balance	108	3,400	108	3,400
With required reserve recorded, Required Reserve	12	273	12	273
With required reserve recorded, Average Carrying Value	102	169	102	143
Carrying Value	101	356	101	356
Unpaid Principal Balance	108	3,400	108	3,400
With required reserve recorded, Required Reserve	12	273	12	273
Average Carrying Value	102	357	102	465
Commercial and Industrial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
With no required reserve recorded, Carrying Value	32	11	32	11
With no required reserve recorded, Unpaid Principal Balance	32	42	32	42
With no required reserve recorded, Required Reserve	0	0	0	0
With no required reserve recorded, Average Carrying Value	47	11	40	71
With required reserve recorded, Carrying Value	563	1,082	563	1,082
With required reserve recorded, Unpaid Principal Balance	765	1,332	765	1,332
With required reserve recorded, Required Reserve	43	353	43	353
With required reserve recorded, Average Carrying Value	644	1,095	722	1,104
With required reserve recorded, Interest Income Recognized	5	8	11	19
Carrying Value	595	1,093	595	1,093
Unpaid Principal Balance	797	1,374	797	1,374
With required reserve recorded, Required Reserve	43	353	43	353
Average Carrying Value	691	1,106	762	1,175
Interest Income Recognized	5	8	11	19
Municipal [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
With no required reserve recorded, Required Reserve	0		0
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
With no required reserve recorded, Carrying Value		400		400
With no required reserve recorded, Unpaid Principal Balance		400		400
With no required reserve recorded, Required Reserve	0	0	0	0
With no required reserve recorded, Average Carrying Value	196	100	280	80
With required reserve recorded, Carrying Value	1,705	4,375	1,705	4,375
With required reserve recorded, Unpaid Principal Balance	1,801	4,466	1,801	4,466
With required reserve recorded, Required Reserve	108	359	108	359
With required reserve recorded, Average Carrying Value	2,809	4,391	3,286	4,405
With required reserve recorded, Interest Income Recognized	17	36	33	74
Carrying Value	1,705	4,775	1,705	4,775
Unpaid Principal Balance	1,801	4,866	1,801	4,866
With required reserve recorded, Required Reserve	108	359	108	359
Average Carrying Value	3,005	4,491	3,566	4,485
Interest Income Recognized	17	36	33	74
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
With no required reserve recorded, Carrying Value	126	70	126	70
With no required reserve recorded, Unpaid Principal Balance	210	70	210	70
With no required reserve recorded, Required Reserve	0	0	0	0
With no required reserve recorded, Average Carrying Value	129	31	131	104
With no required reserve recorded, Interest Income Recognized	2		4
With required reserve recorded, Carrying Value	815	1,489	815	1,489
With required reserve recorded, Unpaid Principal Balance	815	1,684	815	1,684
With required reserve recorded, Required Reserve	41	160	41	160
With required reserve recorded, Average Carrying Value	817	1,106	820	1,039
With required reserve recorded, Interest Income Recognized	1	3	7	5
Carrying Value	941	1,559	941	1,559
Unpaid Principal Balance	1,025	1,754	1,025	1,754
With required reserve recorded, Required Reserve	41	160	41	160
Average Carrying Value	946	1,137	951	1,143
Interest Income Recognized	3	3	11	5
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
With no required reserve recorded, Required Reserve	0	0	0	0
Home Equity [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
With no required reserve recorded, Required Reserve	0	0	0	0
With required reserve recorded, Carrying Value	91	93	91	93
With required reserve recorded, Unpaid Principal Balance	91	93	91	93
With required reserve recorded, Required Reserve	91	93	91	93
With required reserve recorded, Average Carrying Value	91	94	92	94
Carrying Value	91	93	91	93
Unpaid Principal Balance	91	93	91	93
With required reserve recorded, Required Reserve	91	93	91	93
Average Carrying Value	$ 91	$ 94	$ 92	$ 94

Allowance for Loan Losses - Add

Allowance for Loan Losses - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Receivables [Abstract]
Troubled debt restructurings, subsequently defaulted	$ 0	$ 0

Reclassifications Out of Accu43

Reclassifications Out of Accumulated Other Comprehensive Income - Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net gains on sales of securities	$ 118		$ 118
Interest on securities held-to-maturity	9,371	$ 8,020	17,539	$ 15,800
Provision for income taxes	(233)	(231)	(448)	(524)
Net income	5,925	5,599	10,884	10,531
Salaries and employee benefits	(9,480)	(8,776)	(18,614)	(17,651)
Reclassification Out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	885	752	1,407	1,619
Reclassification Out of Accumulated Other Comprehensive Income [Member] | Unrealized Gains and Losses on Available-for-Sale Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net gains on sales of securities	118		118
Provision for income taxes	(47)		(47)
Net income	71		71
Reclassification Out of Accumulated Other Comprehensive Income [Member] | Accretion of Unrealized Losses Transferred [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest on securities held-to-maturity	1,576	1,286	2,705	2,793
Provision for income taxes	(549)	(478)	(943)	(1,061)
Net income	1,027	808	1,762	1,732
Reclassification Out of Accumulated Other Comprehensive Income [Member] | Prior-Service Costs [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Salaries and employee benefits	(3)	(3)	(6)	(5)
Reclassification Out of Accumulated Other Comprehensive Income [Member] | Actuarial Gains (Losses) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Salaries and employee benefits	(352)	(91)	(704)	(183)
Reclassification Out of Accumulated Other Comprehensive Income [Member] | Amortization of Defined Benefit Pension Items [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before taxes	(355)	(94)	(710)	(188)
Provision for income taxes	142	38	284	75
Net income	$ (213)	$ (56)	$ (426)	$ (113)

Earnings per Share ("EPS") - Ad

Earnings per Share ("EPS") - Additional Information (Detail) - shares	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Number of Stock options outstanding		0
Class A Common Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of stock options, increment in shares	1,327		1,452
Class A Common Stock [Member] | Minimum [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Class A common stock entitled dividend per share percent in comparison to Class B common stock		200.00%

Earnings Per Share ("EPS") - Re

Earnings Per Share ("EPS") - Reconciliation of Basic EPS and Diluted EPS (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 5,925	$ 5,599	$ 10,884	$ 10,531
Class A Common Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 4,654	$ 4,394	$ 8,549	$ 8,259
Weighted average shares outstanding, basic	3,600,729	3,589,125	3,600,729	3,585,773
Basic earnings per share	$ 1.29	$ 1.22	$ 2.37	$ 2.30
Dilutive effect of Class A stock options		1,327		1,452
Weighted average shares outstanding, diluted	5,567,909	5,558,032	5,567,909	5,558,105
Diluted earnings per share	$ 1.06	$ 1.01	$ 1.95	$ 1.89
Class B Common Stock [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Net income	$ 1,271	$ 1,205	$ 2,335	$ 2,272
Weighted average shares outstanding, basic	1,967,180	1,967,580	1,967,180	1,970,880
Basic earnings per share	$ 0.65	$ 0.61	$ 1.19	$ 1.15
Weighted average shares outstanding, diluted	1,967,180	1,967,580	1,967,180	1,970,880
Diluted earnings per share	$ 0.65	$ 0.61	$ 1.19	$ 1.15

Employee Benefits - Additional

Employee Benefits - Additional Information (Detail) - 6 months ended Jun. 30, 2015 - USD ($)	Total
Compensation and Retirement Disclosure [Abstract]
Number of years service to participate in supplemental plan	1 year
Current fiscal year contribution to pension plan	$ 1,000,000
Employer expected contribution to Pension Plan in 2015	$ 2,000,000

Employee Benefits - Components

Employee Benefits - Components of Net Periodic Benefit Cost (Credit) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 336	$ 258	$ 672	$ 516
Interest	394	367	788	734
Expected return on plan assets	(688)	(636)	(1,376)	(1,272)
Recognized prior service cost (benefit)	(26)	(26)	(52)	(52)
Recognized net actuarial losses	204	3	407	6
Net periodic benefit (credit) cost	220	(34)	439	(68)
Supplemental Insurance/ Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	397	389	794	778
Interest	341	331	682	662
Recognized prior service cost (benefit)	29	29	58	58
Recognized net actuarial losses	149	88	299	176
Net periodic benefit (credit) cost	$ 916	$ 837	$ 1,833	$ 1,674

Fair Value Measurements - Finan

Fair Value Measurements - Financial Instruments Measured at Fair Value on a Recurring and Non-recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	$ 440,059	$ 448,390
Fair Value Measurements, Level 1 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	287	296
Fair Value Measurements, Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	287,194	351,208
Fair Value Measurements, Level 3 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	152,578	96,886
Financial Instruments Measured at Fair Value on a Non-recurring Basis
Impaired Loans	1,159	3,410
Other Real Estate Owned	1,916
U.S. Treasury [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	1,997	2,000
U.S. Treasury [Member] | Fair Value Measurements, Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	1,997	2,000
Small Business Administration [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	6,494	6,717
Small Business Administration [Member] | Fair Value Measurements, Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	6,494	6,717
U.S. Government Agency and Sponsored Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	273,563	337,093
U.S. Government Agency and Sponsored Mortgage Backed Securities [Member] | Fair Value Measurements, Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	273,563	337,093
Privately Issued Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	1,641	1,874
Privately Issued Residential Mortgage Backed Securities [Member] | Fair Value Measurements, Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	1,641	1,874
Obligations Issued by States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	152,541	96,784
Obligations Issued by States and Political Subdivisions [Member] | Fair Value Measurements, Level 3 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	152,541	96,784
Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	3,499	3,524
Other Debt Securities [Member] | Fair Value Measurements, Level 2 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	3,499	3,524
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	324	398
Equity Securities [Member] | Fair Value Measurements, Level 1 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	287	296
Equity Securities [Member] | Fair Value Measurements, Level 3 Inputs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	37	102
Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	440,059	448,390
Financial Instruments Measured at Fair Value on a Non-recurring Basis
Impaired Loans	1,159	3,410
Other Real Estate Owned	1,916
Carrying Value [Member] | U.S. Treasury [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	1,997	2,000
Carrying Value [Member] | Small Business Administration [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	6,494	6,717
Carrying Value [Member] | U.S. Government Agency and Sponsored Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	273,563	337,093
Carrying Value [Member] | Privately Issued Residential Mortgage Backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	1,641	1,874
Carrying Value [Member] | Obligations Issued by States and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	152,541	96,784
Carrying Value [Member] | Other Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	3,499	3,524
Carrying Value [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities AFS	$ 324	$ 398

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) - USD ($)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Specific adjustments to impaired loans recognized	$ 558,000	$ 594,000	$ 947,000
Transfers between level 1 and 2	0	0	0
Liabilities measured at fair value on a recurring or nonrecurring basis	0	0	$ 0
Fair Value Measurements, Level 3 Inputs [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized cost of Level 3 securities	153,454,000	153,454,000		$ 61,577,000
Unrealized loss	$ 876,000	$ 876,000		$ 872,000

Fair Value Measurements - Asset

Fair Value Measurements - Assets Measured at Fair Value (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Securities AFS [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Fair Value	$ 152,578	$ 96,886
Valuation Technique	Discounted cash flow
Unobservable Input	Discount rate
Impaired Loans [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Fair Value	$ 1,159	$ 3,410
Valuation Technique	Appraisal of collateral
Unobservable Input	Appraisal adjustments
Other Real Estate Owned [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Fair Value	$ 1,916
Valuation Technique	Appraisal
Unobservable Input	Appraisal adjustments
Minimum [Member] | Securities AFS [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Unobservable Input Value or Range	0.00%	0.00%
Minimum [Member] | Impaired Loans [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Unobservable Input Value or Range	0.00%	0.00%
Minimum [Member] | Other Real Estate Owned [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Unobservable Input Value or Range	0.00%
Maximum [Member] | Securities AFS [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Unobservable Input Value or Range	1.00%	1.00%
Maximum [Member] | Impaired Loans [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Unobservable Input Value or Range	30.00%	30.00%
Maximum [Member] | Other Real Estate Owned [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Unobservable Input Value or Range	30.00%

Fair Value Measurements - Ass51

Fair Value Measurements - Assets Measured at Fair Value (Parenthetical) (Detail)	6 Months Ended
	Jun. 30, 2015
Municipal [Member]
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Line Items]
Securities maturity period

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Level 3 Securities (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 96,886	$ 36,597
Purchases	113,179	51,471
Maturities and calls	(57,476)	(27,361)
Amortization	(11)	(2)
Changes in fair value	0	0
Ending Balance	152,578	60,705
Auction Rate Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	3,820	3,820
Changes in fair value	0	0
Ending Balance	3,820	3,820
Obligations Issued by States and Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	92,964	32,487
Purchases	113,179	51,471
Maturities and calls	(57,411)	(27,282)
Amortization	(11)	(2)
Changes in fair value	0	0
Ending Balance	148,721	56,674
Equity Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	102	290
Maturities and calls	(65)	(79)
Changes in fair value	0	0
Ending Balance	$ 37	$ 211

Fair Values of Financial Inst53

Fair Values of Financial Instruments - Carrying Amount and Fair Value of Company's Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Financial assets:
Securities held-to-maturity	$ 1,683,568	$ 1,406,792
Loans	1,522,449	1,309,048
Financial liabilities:
Time deposits	383,284	383,145
Other borrowed funds	485,500	395,500
Subordinated debentures	36,083	36,083
Carrying Value [Member]
Financial assets:
Securities held-to-maturity	1,683,568	1,406,792
Loans	1,522,449	1,309,048
Financial liabilities:
Time deposits	383,284	383,145
Other borrowed funds	485,500	395,500
Subordinated debentures	36,083	36,083
Estimated Fair Value [Member]
Financial assets:
Securities held-to-maturity	1,689,572	1,413,603
Loans	1,503,326	1,291,550
Financial liabilities:
Time deposits	387,675	387,919
Other borrowed funds	487,271	400,196
Subordinated debentures	36,083	36,083
Fair Value Measurements, Level 2 Inputs [Member]
Financial assets:
Securities held-to-maturity	1,689,572	1,413,603
Financial liabilities:
Time deposits	387,675	387,919
Other borrowed funds	487,271	400,196
Fair Value Measurements, Level 3 Inputs [Member]
Financial assets:
Loans	1,503,326	1,291,550
Financial liabilities:
Subordinated debentures	$ 36,083	$ 36,083