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Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands | Total | Common Stock [Member] | Additional paid-in capital [Member] | Retained Earnings [Member] | Accumulated other comprehensive (loss) income [Member] | Treasury stock [Member]
--- | --- | --- | --- | --- | --- | ---
Balance at beginning of year, as adjusted |  |  |  |  | $ 1,446,192 | $ (9,425) |
Beginning of year at Dec. 31, 2015 |  |  | $ 201,723 | $ 326,656 | 1,446,192 | (9,425) | $ (567,105)
Dividend reinvestment plan (shares: 23,493 – 2018; 28,607 – 2017; 38,741 – 2016) |  |  | 77 | 1,389 |  |  |
Stock purchase and compensation plans (shares: 540,337 – 2018; 635,521 – 2017; 720,323 – 2016) |  |  | 1,441 | 19,250 |  |  |
Net income |  | $ 158,495 |  |  | 158,495 |  |
Dividends to stockholders ($0.74 per share – 2018; $0.66 per share – 2017; $0.61 per share – 2016) |  |  |  |  | (35,806) |  |
Other comprehensive (loss) income |  | (6,525) |  |  |  | (6,525) |
Acquisition of treasury stock (shares: 110,398 – 2018; 136,205 – 2017; 152,595 – 2016) |  |  |  |  |  |  | (4,992)
End of year at Dec. 31, 2016 |  | 1,531,370 | 203,241 | 347,295 | 1,568,881 | (15,950) | (572,097)
Cumulative effect adjustment | Accounting Standards Update 2016-01 [Member] |  | 0 |  |  | 0 | 0 |
Cumulative effect adjustment | Accounting Standards Update 2018-02 [Member] |  |  |  |  | 0 | 0 |
Balance at beginning of year, as adjusted |  |  |  |  | 1,568,881 | (15,950) |
Dividend reinvestment plan (shares: 23,493 – 2018; 28,607 – 2017; 38,741 – 2016) |  |  | 57 | 1,395 |  |  |
Stock purchase and compensation plans (shares: 540,337 – 2018; 635,521 – 2017; 720,323 – 2016) |  |  | 1,271 | 19,027 |  |  |
Net income |  | 168,826 |  |  | 168,826 |  |
Dividends to stockholders ($0.74 per share – 2018; $0.66 per share – 2017; $0.61 per share – 2016) |  |  |  |  | (39,094) |  |
Other comprehensive (loss) income |  | 36,120 |  |  |  | 36,120 |
Acquisition of treasury stock (shares: 110,398 – 2018; 136,205 – 2017; 152,595 – 2016) |  |  |  |  |  |  | (6,015)
End of year at Dec. 31, 2017 |  | 1,712,957 | 204,569 | 367,717 | 1,698,613 | 20,170 | (578,112)
Cumulative effect adjustment | [1] |  |  |  |  | (25,019) |
Cumulative effect adjustment | Accounting Standards Update 2016-01 [Member] |  | 0 |  |  | 0 | 0 |
Cumulative effect adjustment | Accounting Standards Update 2018-02 [Member] |  |  |  |  | 0 | 0 |
Balance at beginning of year, as adjusted |  |  |  |  | 1,723,632 | (4,849) |
Dividend reinvestment plan (shares: 23,493 – 2018; 28,607 – 2017; 38,741 – 2016) |  |  | 47 | 1,379 |  |  |
Stock purchase and compensation plans (shares: 540,337 – 2018; 635,521 – 2017; 720,323 – 2016) |  |  | 1,081 | 21,219 |  |  |
Net income |  | 178,939 |  |  | 178,939 |  |
Dividends to stockholders ($0.74 per share – 2018; $0.66 per share – 2017; $0.61 per share – 2016) |  |  |  |  | (44,157) |  |
Other comprehensive (loss) income |  | (73,107) |  |  |  | (73,107) |
Acquisition of treasury stock (shares: 110,398 – 2018; 136,205 – 2017; 152,595 – 2016) |  |  |  |  |  |  | (6,556)
End of year at Dec. 31, 2018 |  | 1,791,802 | $ 205,697 | $ 390,315 | 1,858,414 | (77,956) | $ (584,668)
Cumulative effect adjustment | Accounting Standards Update 2016-01 [Member] |  | $ (30,726) |  |  | 30,726 | (30,726) |
Cumulative effect adjustment | Accounting Standards Update 2018-02 [Member] |  |  |  |  | $ (5,707) | $ 5,707 |
[1] | Upon adoption of ASU 2016-01 and ASU 2018-02 in the first quarter of 2018, we recognized a $25.0 million cumulative-effect adjustment to the opening balance of AOCI, which represents the after-tax net unrealized gain on our equity portfolio as of December 31, 2017 and the one-time reclassification from AOCI to retained earnings for the stranded tax assets that were created in AOCI from the enactment of Tax Reform. See Note 3. "Adoption of Accounting Pronouncements" above for additional information.

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