Goodwill and Intangible Assets |
5. Goodwill and Intangible Assets Changes in the carrying amount of goodwill during the years ended December 31, 2019 and 2018 are as follows (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | | Travel Network | | Airline Solutions | | Hospitality Solutions | | Total Goodwill | Balance as of December 31, 2017 | $ | 2,104,822 | | | $ | 290,985 | | | $ | 159,180 | | | $ | 2,554,987 | | | | | | | | | | Adjustments(1) | (33) | | | 378 | | | (2,963) | | | (2,618) | | Balance as of December 31, 2018 | 2,104,789 | | | 291,363 | | | 156,217 | | | 2,552,369 | | Acquired | — | | | 82,402 | | | — | | | 82,402 | | Adjustments(1) | (7) | | | (107) | | | (1,406) | | | (1,520) | | Balance as of December 31, 2019 | $ | 2,104,782 | | | $ | 373,658 | | | $ | 154,811 | | | $ | 2,633,251 | |
________________________ (1)Includes net foreign currency effects during the year. The following table presents our intangible assets as of December 31, 2019 and 2018 (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2019 | | | | | | December 31, 2018 | | | | | | Gross Carrying Amount | | Accumulated Amortization | | Net Carrying Amount | | Gross Carrying Amount | | Accumulated Amortization | | Net Carrying Amount | Acquired customer relationships | $ | 1,046,382 | | | $ | (735,367) | | | $ | 311,015 | | | $ | 1,033,555 | | | $ | (709,824) | | | $ | 323,731 | | Trademarks and brand names | 333,638 | | | (147,735) | | | 185,903 | | | 332,239 | | | (137,009) | | | 195,230 | | Reacquired rights | 113,500 | | | (73,124) | | | 40,376 | | | 113,500 | | | (56,910) | | | 56,590 | | Purchased technology | 437,288 | | | (409,204) | | | 28,084 | | | 426,488 | | | (400,750) | | | 25,738 | | Acquired contracts, supplier and distributor agreements | 37,599 | | | (29,324) | | | 8,275 | | | 37,600 | | | (25,867) | | | 11,733 | | Non-compete agreements | 14,686 | | | (14,686) | | | — | | | 14,686 | | | (14,460) | | | 226 | | Total intangible assets | $ | 1,983,093 | | | $ | (1,409,440) | | | $ | 573,653 | | | $ | 1,958,068 | | | $ | (1,344,820) | | | $ | 613,248 | |
Amortization expense relating to intangible assets subject to amortization totaled $65 million, $68 million and $96 million for the years ended December 31, 2019, 2018 and 2017, respectively. Estimated amortization expense related to intangible assets subject to amortization for each of the five succeeding years and beyond is as follows (in thousands): | | | | | | 2020 | $ | 65,915 | | 2021 | 64,337 | | 2022 | 50,736 | | 2023 | 37,030 | | 2024 | 58,395 | | 2025 and thereafter | 297,240 | | Total | $ | 573,653 | |
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