We recognized approximately $24.1 million in impairment and other charges, $18.0 million of which primarily relates to the partial impairment of certain intangible assets recorded in the 2012 acquisition of Easy Choice. The remaining charges also include a charge for the full impairment of intangible assets associated with the purchase of our Arizona MA plan after we concluded during 2014 to exit the Arizona MA market in 2015, and charges resulting from the resolution of certain matters related to the purchase price of our 2013 acquisitions.
acquisition of Easy Choice Health Plan, Inc. (“Easy Choice”). These decreases were partially offset by the increase in premiums from organic membership growth and acquisitions, lower administrative expenses as a percentage of total revenues and the Windsor bargain purchase gain, which amounted to $29.5 million in 2014. Refer to Segment Reporting below for a discussion of current developments, operating results and other key performance measures by reportable segment.
Premium revenue for the year ended December 31, 2013 increased approximately $2.1 billion, or 28%, compared to the same period in 2012. The increase is primarily attributable to our 2012 and 2013 acquisitions, which collectively contributed $913.4 million, or 12%, to the year-over-year increase, organic membership growth in our Medicaid and Medicare Health Plans segments and rate increases in certain of our Medicaid markets, including the 7% increase in Kentucky that was effective January 1, 2013. Additionally, the increase was partially attributable to Medicaid revenue from payment arrangements with certain states associated with primary care enhanced payments, as mandated by the ACA. These increases were partially offset by the impact of lower membership in our Medicare PDPs segment. Premium revenue included $75.7 million and $82.2 million of Medicaid premium taxes for the years ended December 31, 2013 and 2012, respectively.
allocation, which includes reviewing the results of Medicare Supplement and Medicare Advantage operations acquired as part of the Windsor acquisition together with MA. Accordingly, we include results for Medicare Supplement operations together with MA and renamed the segment Medicare Health Plans. Similarly, we include the PDP operations acquired as part of the Windsor acquisition together with WellCare’s PDPs and renamed the segment Medicare PDPs. No changes were made to the composition of our Medicaid segment, but we renamed the segment Medicaid Health Plans.
“All other states” consists of Hawaii, Illinois, and New York during all years presented. In 2012, it also includes Ohio; in 2013, it also includes Missouri and South Carolina; and in 2014, it also includes Missouri, New Jersey and South Carolina. Effective as of June 30, 2012, our Missouri contract expired and was not renewed. We re-entered Missouri Medicaid in March 2013 when we acquired Missouri Care. We were not awarded a Medicaid contract in Ohio for the 2013 fiscal year; however, the state of Ohio contracted with us to provide services to Ohio Medicaid beneficiaries through a transition period, which ended June 30, 2013.
The following table sets forth the summarized results of operations and other relevant performance measures for our Medicare Health Plans segment for the years ended December 31, 2014, 2013 and 2012:
PDP membership as of January 1, 2015 was 1,098,000, a decrease of approximately 294,000, or 21%, from 1,392,000 as of December 31, 2014. The decline in membership in 2015 is primarily based on the outcome of our 2015 PDP bids, in which our plans were below the benchmarks in 13 of the 33 CMS regions for which we submitted bids and in the de minimis range in nine regions. In 2015, those PDP members who were auto assigned to us in regions where our plans are not below or within the de minimis range were or are being assigned to other plans. However, the outcome of our 2015 bids is expected to have a favorable impact on the 2015 segment results compared to 2014, as discussed above.
We currently maintain directors' and officers' liability insurance in the amount of $125.0 million for other matters not addressed above.
For additional information on regulatory requirements, see Note 17 - Regulatory Capital and Dividend Restrictions to the Consolidated Financial Statements.
Coverage Gap Discount Subsidy (CGD)- CMS provides monthly prospective payments for pharmaceutical manufacturer discounts made available to members.